In a study of brachiopods in the National Museum, Dall (1920) assigned type localities for each of the species. All scattered specimens of these three genera are more like those of the Baja California Abyssal Plain than Dall and Davidson type specimens. In the Permian, Cryptacanthia and Glossothyropsis are nearly identical homeomorphs of the two modern genera.
The fact that the homeomorphs of the Baja California Abyss are deep-water, and that these genera are deep-water wherever they are found, suggests that sulcation may be a deep-water phenomenon. This proposal could also apply to the association of the Paranorella and Glossothyropsis homeomorphs in the Permian. Although black, the pebbles to which some specimens are attached are not soft or tarry.
The problem of species establishment associated with the Baja California Abyssal Plain homeomorphs is an excellent example of the difficulties taxonomists face. In this case, the three species from the Baja California Abyssal Plain do not correspond to the type species of the genera involved. None of the type species are represented by samples sufficient to establish a species beyond doubt.
Many Abyssothyris and Neorhynchia from the Abyssal Plain of Baja California, although showing some variation in many characters, are uniform in their general expression, i.e., shell elongation.
FIGURES 1-11
It will take a great deal of deep exploration to collect enough material to demonstrate that these three genera are indeed each represented by a single species. As in its homeomorph Abyssothyris, variation in the fold of the anterior commissure in Neorhynchia is evident to a marked degree. Most shells, after becoming adults, have a broad, smooth wave of the anterior margin, such as U S N M 550392d.
DISCUSSION. Prior to the collection of the specimens on which the above description is based, Neorhynchia was a very rare genus known only from the types and a few other individuals, such as those incorrectly identified as Abyssothyris (Muir-Wood, 1960). ). Beak narrowly swollen; umbonal area swollen and narrow, the swelling continues to the anterior edge of the anterior margin to form a moderate to deep fold that receives the tongue of the dorsal valve. This is short and of the plectolophous type with two lobes on each side and two smaller ones in the center.
The smaller lobe is immersed dorsally to the larger one and is suspended from the anterior part of the crural process. The posterior part of the lophophore is suspended across the gap between the cranial processes. Two species of the genus are known at the present time—a fossil, A. 7) from the Miocene-Lower Pliocene of Fiji, and a recent one, A.
T he three specimens in the collection of the National Museum of Natural History are smaller than any of those figured by Davidson or those from the Baja California Abyssal Plain. 10 m m, but none of them are wider than long, although their L/W ratios are less than those of the adults. Twenty-one percent of the samples in this lot measured 10 m m or less and their average L/W index was 1.12.
Only five percent of specimens measured over 19 mm, and these had an average L/W ratio of 1.37. This group averaged somewhat higher than specimens of the same measurement range from locality S 1070-22. The elongate shape of the species is very noticeable and contrasts strongly with the lectotype of A.
Wl DTH
FIGURES 23-29; PLATE 3 : FIGURES 1-19
This species is distinguished by its elongated-oval to pentagonal outline, great depth of the adult and strong, rather narrow fold. They show no traces of the dark brown periostracum resembling that which occurs on parts of N. The validity of the name Notorygmia abyssa, a new species, will hold unless or until Waldheimia wyvillei Davidson, described below, can be proven to be sulcate and to belong to Notorygmia.
H o w a r d Brunton, Keeper of the Recent Brachiopoda at the British Museum (Natural History), kindly examined this specimen for me, and later, in a hasty visit to the British Museum, I had an opportunity of studying it. Most of the ventral valve has been broken away and the anterior margin has been destroyed. This damage has the advantage of giving a view of the interior where the critical characters reside, but it hides vital exterior characters.
These two characters, combined with the open nature of the foramen, clearly indicate the diagnostic characters of Macandrevia. The fact that Waldheimia wyvillei occurs with Abyssothyris wyvillei suggests the possibility that it is a species of Notorygmia and another example of the homeomorphy which forms the subject of this paper, but rules out Davidson's clear statement that his species is without a sinus. out of that possibility. Annotated List of Recent Brachiopoda in the Collection of the United States National Museum, with Descriptions of Thirty-Three New Species.
Publications of the University of California at Los Angeles in Mathematical and Physical Sciences plates. Figures Anterior, dorsal, lateral and ventral views (X 1) of the holotype (USNM dorsal view (X 2) of the holotype; 6, 7, posterior tilted and dorsal views (X 4) of the posterior part of the holotype showing the hypothyridial foramen, disjoint deltidial plates and tooth plates; 8-10, ventral, posteriorly tilted and laterally tilted views. X 4) of the cardinalia of the holotype showing the falcifer crura, slight median ridge, strong socket ridges and outer hinge plates; 11, interior of dorsal valve (X 4) of a paratype (USNM 110741a), younger than the holotype, with cardinalia. Figure Pebble (X 1) with attached Neorhynchia on the left and an Abyssothyris on the right (paratype, USNM dorsal view (X 3) of a complete specimen (para-type, USNM 550433) in alcohol showing the spirolopous lophophore with left partially unrolled toe; 18, interior (X 2) of a mature dorsal valve (paratype, USNM 550394t) showing cardinalia and muscle scars; 19, ventral view (X 2) of a specimen (paratype, USNM 550434) in alcohol with part of the ventral valve removed showing the spiral lophophore from the ventral side; 20, 21, interior (X 3) of the ventral and dorsal valves of a young adult (paratype, USNM 550393m) showing teeth, hypothyroid foramen and showing well-developed, short cardinalia; 22 , interior (X 2) of a large adult (paratype, USNM 550435) in alcohol, with part of the dorsal valve removed to show the spirolophe.
Figures Dorsal, anterior, ventral, posterior and lateral views (X 1) of a complete specimen (paratype, USNM laterally inclined and ventral view (X 2) of the interior of the dorsal valve of the previous paratype showing the long, unsupported or dalliniform loop. 36, dorsal view (X 2) of a specimen (paratype, U S N M 550398i) with a broken dorsal valve showing the dorsum of the loop, which has an unusually broad transverse band; 37, lateral view (X 2.5) of a specimen (paratype, USNM 550398y) with the peduncle valve removed , to show plectolophus lophophore and short frayed petiole Manuscripts for serials are accepted by the Smithsonian Institution Press, subject to substantive review, only through departments of the various Smithsonian museums.
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