Meanwhile, in the publication of some of the results of his studies, Prof. 1 The shoulder girdle of the Elasmobranchiates appears to be homologous to the paraglenal or coracoid element (ride postea) of the specialized fishes, the proscapula of the latter having apparently developed first by exostosis in the Ganoids and.
ORDERS OF PISCES
All the orders thus adopted appear, so far as appears from considerable material, to be well distinguished by peculiarities of the skeleton and nervous system. The peculiarities of the skeleton are manifested in the skull, (1) especially in the varying combinations of the elements composing the cranial case, as well as (2) the palato-pterygoid system, and (3) the suspensorium of the mandible. , while in (4) the changes to the pectoral girdle other excellent characters are found.
EXCURSUS OX THE SHOULDER GIRDLE OF FISHES
For example, the large frontal bone in the Gadinae and related subfamilies is single, asin. The lower pharyngeal bones are generally separate in the Teleocephala, but in several families they are united more or less early, and in the extreme forms very soon, they lose all traces of the suture, and the eminent Johannes Midler was led to separate the forms so distinguished from others fish as a special order (Pharyngognathi); that such a combination was, however, somewhat hasty, may be proved, independently of hypothetical considerations as to the value of signs by certain facts.
THE GIEDLE IN DIPNOANS
The articulation of the front limb with the shoulder girdle is the most obvious and identifiable point for comparison in representatives of individual classes. It is equally impossible to identify the fish elements with those of the higher reptiles or other vertebrates evolved from the Batrachians.
CHARACTERISTICS AND SEQUENCE OF PRIMARY GROUPS
The lengths of the cartilaginous glenoid region may be accepted, and the oracoid would then be (partially) represented by the element so named by Owen.
MARSIPOBEANCHIATES
XX. are Marsipobranchiates (Lampreys, etc.), and the tendency has been to overlook the fundamental differences between the two and to get too close to them, rather than the other way around. But agreement ends, and much difference of opinion prevails as to the succession in the system of the several sub-classes (by whatever name) of true fishes, (1) some (e.g. Cuvier, J. Muller, Owen, Liitken, Cope) being arranged next to the lowest , Elasmobranchiates and, successively, Ganoids and Teleosteans, (2) while others (e.g. Agassiz, Dana, Dumeril, Giinther) accept the order Leptocardians, Mar-.
ELASMOBRANCHIATES
The evidence of the closer affinity of the Elasmobranchiates (than of any other fish) with the Marsipobranchiates is furnished by (1) the cartilaginous condition of the skeleton; (2) the post-cephalic position of the takhe; (3) the development of the branchiae, and their restriction to special chambers; (4) the greater number of branchiae; (5) the imperfect development. In any case, however, the general or rudimentary condition of the organs points to the still more general, rudimentary, or undeveloped condition exhibited by the Marsipobranchiates.
PLAGIOSTOMI
In none of these cases is there an exact resemblance, or even a very close one, for, as already observed, the gulf between the Fishes (and the Elasmobranehiates as the most generalized form) and the Marsipobranchiates is exceedingly wide. And still more, there are no other forms which can be compared with the Marsipobranchiates in a manner even nearly so satisfactory.
HOLOCEPHALI
The testimony of these parts is also concurrent, reinforced by other similarities, less obvious but valuable as cumulative, and not counterbalanced by the evidence of other parts (unless the non-relative specialization of isolated parts is taken as contradictory evidence ).
GANOIDEI
Johannes Miiller, on the anatomy and classification of fishes, reached the long climax in his famous memoirs on those fishes to which he retained the ordinal name of Ganoidei; those memoirs have left an impression on ichthyology perhaps more decided than any other contribution to science, and those published indefinitely will always be classics; Numerous as have been the modifications since introduction into the system, no forms other than those known to Miiller (unless Dipnoi) have since intermingled among the Ganoids. Without notice in any other form, the results of his studies on the Ganoids were announced to the Royal Academy of Sciences in Berlin in
XXIV
The failure of the intestinal spiral valve, as a diagnostic character, has long been admitted, and. in this case, have only the forms that prove the error referred to; in the other cases, where it would be particularly desirable to have stated the actual types which falsify the universality or exclusivity of the characters, they have not been referred to, and the objections must be met as if. they were not known to exist. But it is quite possible that among some of the generalized Teleosts at least traces of some of the characters now considered peculiar to the Ganoids may be discovered.
XXVU1
EXCURSUS ON THE PECTORAL LIMB
XXIX. of direct rays with the scapular arch) expressions of factual matters and partly the interpretation of homologies. But the Crossopterygians agree better with the latter in the composition of the skull and squamation, and therefore the question arises whether it is.
CHONDROGANOIDS
Possibly the following hypothesis may approach the truth and account for the divergences between the different types. The Acanthodeans of the Devonian and following epochs may be the nearest relatives known to the representatives of the direct line of descent from the typical Elasmobranchiates; The development of two marginal (external and internal) spines in the sternum may give importance to the specialized condition of the metapterygium and propterygium in the pectoral limbs of the subsequent forms, which may also characterize the scales of those of the typical "ganoid" type.
BBACHIOGAXOID AND DIPNOAN OFFSHOOTS
XXXI
GENALOGICAL TKEE OF GANOIDS
ACANTHODEI
SUPERORDER BRACHIOGANOIDEI
XXXIV
XXXV
XXXVI
TELEOST SEKIES
TELOCEPHALI
The frontal bones may be single or double, the anterior sphenoid (Cuv.) may be present or absent, the palatine and pterygoid bones may be distinct, or (as in the electric eel) partially fused, the scapular arch may be attached by one or two processes to the skull, a mesocoracoid may or. The brain, heart and vascular system in general, and hyo-branch apparatus are fundamentally similar, but exhibit (especially the last) slight modifications which indicate narrower differences, and which may be used in distinguishing inferior groups.
SCYPHOPHORI
It is also quite possible that evidence of the superior rights of such claimants may be adduced; it may have been proved that such have altogether more in common with the ancient types than those forms now recognized by the rank, and that the specialized features which they now exclude are out of harmony with other equally specialized characters, and have no meaning as now it seems, but so given the present evidence, the teleocephalic claims of Physiostomes seem to be superior to those of the other forms.
NEMATOGNATHI
APODES
Synentognaths) and, on the other, so much differing from the next allied forms that the requirements of classification seem best met by their union in one order. Their affinities through the more generalized forms of the order are possibly with the Gymnonoti, but the hints from the elongate body and the increased number of vertebrae, etc., may be illusive.
OPISTHOMI
HEMIBEANCHII
LOPHOBRANCHII
The order (at least after the exclusion of the Pegasid family) was almost universally recognized.
PIECTOGNATHI
They are mainly characterized by the development of the scapular arch (hypercoracoid atrophied in the Gymnodonts), the degree of union of the jaws and dentition, and by the squamation. Cope has considered the relationships of the order (through the Triacanthise on the one hand and the Chaetodontidae and Acronuridae on the other) to be most intimate with the Teleocephala at the point indicated, and M.
GENETIC RELATIONS AND SEQUENCES
The main problem regarding them is therefore limited to the question of the taxonomic value of the characters that distinguish them from other forms. According to the isolation of the group, the conspicuousness of the characters by which they are distinguished, and the disturbance which would be caused by their intrusion among the teleocephali, we distinguish them in order.
GANOID SERIES
ACANTHODEI (VII.)
1 RHOMBOOANOIDEA (XII.)
CHONDROSTEI (VIII.)
BATRACHIA— REPTILIA.\
ELASMOBRANCHII
HOLOCEPHALI (VL)
3 — HYPEROARTIA (III
SQUALI (IV.)
NEMATOONATHI (XVI.)
Assuming that the Gymnonoti, the Scyphophori and the Nematoqxatiii on the one hand, and the Apodes on the other, are derivatives of the Physostome Teleocephals or their immediate ancestors, they should perhaps be projected after the Teleocephals as successively more differentiated offshoots, but for the time being it is at least case considered advisable to keep them in the usual position; However, it must be clear that they constitute a divergent line from the supposed commonality. In addition to the orders here mentioned, several others appear to be represented by extinct fishes, but we are not sufficiently aware of the details of their structure to introduce them into the system with certainty.
FAMILIES
It may be suggested, however, that one of the orders consists of the Placoganoidei (when restricted to such forms as the Pterichthyidee and Goccosteidse); another is represented by the Triassic and Cretaceous ganoids with a persistent notochord, common pisciform proportions, and non-lobed pectoral fins, such as the Caturidae. The ordinary or even subordinate value of the group has been admitted by few, and it is generally regarded as a member of the "order Physostomi," and as it is really a natural and homogeneous group, and stands in strong contrast to any other, it is by many been endowed only with family rank.
ACKNOWLEDGMENTS, ETC
The true statement of his current views on the system is embodied in the foregoing essay, and especially in the discussion of the succession of forms. Immediate insertion is the less necessary as the remarks made in the course of this introduction will be sufficient to give an idea of the characters of most of the larger groups adopted.
FAMILIES OF FISHES
PLECTOGNATHI
Orthagoriscidae Gyninodontes (Molina), Gthr
OSTRACODERMI
Balistidae Sclerodermi (Balistina), Gthr
Hippocampidae Syngnathidae (Hippocampi-
Syngnathidae Syngnathidae (Syngnathina)
SOLENOSTOMI
PEDICULATI
TELEOCEPHALI
Macruridae
Congrogadidae
Fierasferidae
Opliidiidae
Brotulidae
Brotulophididae Ophidiidae (Brotulina), Gthr
Ranicepitidae
Gadidae
Merluciidae
Lycodidae
Xenocephaliclae,
Ammodytidae
Gadopsidae
ACANTHOPTERI
Stichaeidae
Xiphidiontidae
Acanthoclinidae
Chaenopsidae
Nemophididae
Anarrhicadidae
Cebidichthyidae
Blenniidae
Batrachidae
Leptoscopidae
Dactyloscopidae
Uranoscopidae
Trachinidae
Phil., 1862, 501-505
Phil., 1862, 501, 505-506
Phil., 1861, 108-117
- Liparididae
- Cyclopteridae
- Platypteridae
- Callionyrnidae
- Gobiidae
- Triglidae
- Agonidae
- Cottidae
- Platycephalidae
- Hemitripteridae
- Scorpaenidae
- Chiridae
- Scaridae
- Chaetodontidae
- Ephippiidae
- Xiphiidae
- Trichiuridae
- Scombridae
- Carangidae
- Drepanidae
- Coryphaenidae
- Nematistiidae
- Stromateidae
- Zenidae
Phil., 1862, 258
- Pteraclididae
- Bramidae
- Lamprididae
- Dianidae
- Kurtidae
- Capridae
- Nomeidae
Phil., 1861, 510-512
Phil., 1861, 512-522
- Nototheniidae
- Bovichthyidae
- Latilidae
- Mullidae
- Polymixiidae Berycidae (Polymixia), Gthr
S., Phil., 1862, 233
17 (Hyodontidae)
EVENTOGNATHI
SCYPHOPHOM
NEMATOGNATHL
ICHTHYOCEPHALI
20 HOLOSTOMI
COLOCEPHALI
CYCLOGANOIDEI
RHOMBOGANOIDEI
CROSSOPTERYGIA
SIRENOIDE1
SELACHOSTOMI
CHONDROSTEI
RAIAE
SQUALL
24 227. Rhinodontidae
HYPEROARTIA
HTPEROTRETI
CIRROSTOMI
BIBLIOGRAPHY
The eels and tentacles (Cobitidae), which have very narrow branchial slits, were counted among fishes with hidden gills, but several species (e.g. Cobitidae, 3sp.) reappear in another work under the genus Enehelyopus,—by the author, who observed the character of branchial openings, he happened to be surprised by the similarity of such forms, which other authors have described with some species. And on comparison it is found that the order of the genera is entirely different from that of the sixth edition, and essentially similar to that followed by Gronovius: it differs in the following respects: — the order of the orders is reversed, and Plagurius is added as the first order; Chondropterygii various; this sequence is reversed in the genera of the orders (III) Branchiostegii and (V) Malacopterygii; and the following additional genera included, namely: — 113, Gobius and 114, Xiphias, between 112, Blennius and 115, Scomber; 113, Ophidion* as the last genus of Acanthopterygii; 144, Stromateus, in Malacopterygii, among 143,.
INDEX
