S. NATIONAL MUSEUM

EXPLANATION OF PLATES

U. S. NATIONAL MUSEUM

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BULLETIN 115 PL. 2

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Hadrocrinus discus, Himerocrinus plenissimus, Marsipocrinus striatus, and M. tennesseensis.

For explanationof plate see pageei.

Plate 2.

Page.

HADROCRINUS DISCUS Lyon 9

Fig. 1. Dorsal view of a s])e<'imen obtained since Lyon's time, showing all cliaracters better than the type, namely, the shallow base, with minutenotchesatthe cornersoftheradialsindicatingtheremnants

of atrophied basals; radials indentedby the largestem-lumen, and marked bystriae(not clearlyreproduced in the printed figure) of the hugecolumn facetwhichenveloped them; distribution of pits

uponthe calyxplates; andthe beginningsoftheheavy,biserialarms.

Slightly imder natural size. (See also textfigs. 3and 4.)

Onondaga: Louisville, Kentucky.

HIMEROCRINUS PLENISSIMUS ^(Lyon)

2. Unretouched photographofaspecimenminusthebasals; toshowthe intensesculpturingbygroovesandridgeswhichobscures the suture lines.

Onondaga: Louisville, Kentucky.

MARSIPOCRINUSSTRIATUS Wachsmuth and Springer

3. Detailofpartoftegmenofspecimenfromwhichthe diagram,figure10, Plate1,wasmade, showingthe am])idacraandthepinnule openings towhichtheylead. X2. Silurian: Tennes.see.

MARSIPOCRINUS TENNESSEENSIS Roemer

4. Detailofpartoftegmenwiththepinnulesthemselvesin position,both from thefreebrachialsandfrom theinterrays, corresponding to the openmgsin Comar.thocrinvsandDolatocrutus. X2. Silurian: Ten- nessee.

(Boththelastfrom the author'spaper onScyphoerinus, Plate_9.) 61

Plate 3.

Page.

HIMEROCRINUS PLENISSIMUS ^(Lyon) 12

Fig. 1. Photographicview,butlittleretouched, ofan almostcompletecalyx, showing the contour and surfacesculpturing, from the deep basal cavity (in which the basals are present, though invisible in the shadow, withoutany columnalsattached) to the high ridges at the margin leading directly to the free arms. The generic diagram (textfig. 5)wascomposed chieflyfromthisspecimen, confirmed by

severalothersas tosomedetails.

An

overlapping transversefracture interrupts the normal succession of plates in the upper part, but their arrangementis clear in theright lowersector, where many of the plates are slightly separatedand the suture lines well marked.

Here may be seen a good example of the modified axillary primi- brach, as well as oneofnormal size and form.

On

accountof the intricate sculpturing,no attempthasbeenmadetooutlinetheplates inthe upperpart ofthisfigure, althoughwithproper lightingthey can be traced upon the specimen in the positions shown in the diagram. The specimen isoriented with the posterior interradius atthe lowerright, the smallbasal, here obscured bythe shadowat the bottom ofthe cavity, being plainly visible in the leftanterior position. Thephotograph isslightly undernaturalsize, but owing to foi-eshorteningthe picture appearsstill morereduced. Measuring froml)ase to margin, and allowingforthe overlapping fracture, the spreadofcalyxisat least15 cm. (Peealsotextfig. 5.)

2. Photographof dorsal side ofaspecimenminusbase,showingastyleof

ornament formed chieflybypitsinsteadofgrooves. Here the axil- lary primibrach is of full size throughout. The second inter- brachialrange hasanextraplate in two interrays, so the anal side can not certainlybeidentified.

3. Dorsal (exterior) viewof detached l)atfals ofa similarspecimen, with partofcolumnadheringinthecavity,andradialsattached.

4. Ventral (interior)viewofdetached base, withsome radialsattached, showingdivision ofthebasals,theirdeep inward projection,andthe largepentapetalousaxialopening.

Onondaga: Louisville, Kentucky.

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U. S. NATIONAL MUSEUM ^{BULLETIN 115 PL. 3}

HlMEROCRINUS PLENISSIMUS

For explanation ofplate see page 62.

U. S. NATIONAL MUSEUM

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HlMEROCRlNUS PLENISSIMUS

FOR EXPLANATION^OF PLATE SEE PAGE^63.

Plate 4.

Poge.

HIMEROCRINIIS PLENISSIMUS (Lyon) 12

Fig. 1. Photographofspecimenwitharms andstem, showingsomeofthe small biserial armsto part of their length, and the nodal columnals with numerouscoglikejirocesses,and thin internodals appearingbetween them. Surfaceornament on calyx removed by erosion, but the pits at the corners of the plates, and the lateral ridges along the

radial seriestowardthearmbases, areconspicuous.

2. Dorsal Adewofa specimen with plates well separated at thesutures, having the modified axillary primibrach in both three and four sidedforms.

3. Dorsalviewof basal platesvithseveralincludedcolumnossiclesadher- ingatthebottomofthecavity,from which they have been detached as in figure 2, thisbeing the condition inwhich theyarefrequently found.

4. Dorsal Adew ofa l)ase in same ^condition as the preceding, with some

radialsattached.

Onondaga: Louisville, KentuclvV.

63

Plate 5.

Page.

TECHNOCRINUS NIAGARENSIS, new species 14

Fig. 1, 2. Basalandlateral viewsofthe type;remnantsofspines areseen in place,andsocketsofothers.

Xiagaran (Bobformation): Hardin County, Tennessee.

STEREOCRINUS HELDERBERGENSIS,new species 15 3, 4. Basalandlateralviewsoftype.

5. Platesofanother specimen, showingstriateornamentation.

Helderbergian (Lindenformation): BentonCounty, Tennessee.

DOLATOCRINUS LACUS Lyon 2^

6. A typical specimen, with characteristic outline: the armsare freeon second secundibrach.

7.

A

larger specimen, with greater incorporation of brachials and more pinnule openings.

DOLATOCRINUS PYRAMIDATUS, new species 29 8. 9. Lateralandbasalviewsof type, showingthe characteristiccontour,

taj)eringupward frombroad truncate base involvingmostof first

primibrachandpartofinterbrachial; pinnule openingsare strong.

10. Basalviewof anotherspecimen showingtracesofstellateornament, usuallyremovedbyerosion.

11. The Inroad, truncate baseofa largerspecimen.

DOLATOCRINUS ROTUNDUS, new species 30

12. 13. Basalandlateralviewsoftype,showingtherotund contour, with- out anglesorsurfaceornament.

DOLATOCRINUS MARSHI Lyon 31

14.

A

typicalspecimen, with prominentpinnule openings.

AllexceptNos. 1-5fromtheOnondagaoftheLouisville area.

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U. S. NATIONAL MUSEUM BULLETIN 115 PL. 5

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Technocrinus niagarensis, Stereocrinus heldebergensis, Dolatocrinus LACus, D. pyramidatus, D. rotundus, and D= marshi.

Forexplanation of plate see page 64.