NATURAL SCIENCES OF PHILADELPHIA. 67 



ward about a fourth of an inch, and ends in a transverse truncate border, 

 which in the entire sternum would measure two inches in width. The 

 position of the ento-sternal plate, of the usual form, at the suture of the epi- 

 and hyo-sternal plates would measure 22 lines in breadth. The depth of 

 the episternal to the ento-sternal is 11 lines; the breadth at the posterior 

 suture 14 lines. In the specimen near the median suture there exists a 

 groove, apparently indicating a long narrow scute intervening between the 

 gular scutes, but not reaching the anterior border of the sternum within four 

 lines. This last mark may perhaps be an anomalous one. 



5. Crocodilus aptus. 



Dr. A. R. Roessler, in charge of the Geological Cabinet of the General Land 

 Office, Washington, has submitted to my inspection a specimen from the col- 

 lection consisting of a cervical vertebra of a Crocodile. The specimen was 

 found by Col. John H. Knight, U. S. A., near South Bitter Creek, where it 

 crosses the stage route about 70 miles west of the summit of the Rocky 

 Mountains, in western Wyoming. It is thorougly petrified, and the bone 

 appears to have been of mature age. It has lost the greater part of the neural 

 arch with the dependent processes, but is otherwise perfect. It belonged to an 

 animal about the size of the Mississippi Alligator, and the bone bears a near 

 resemblance with the corresponding sixth or seventh cervical vertebra of that 

 species. The hypapophysis has the same character, projecting obliquely from 

 the fore part of the centrum, but the latter is less carinated back of the pro- 

 cess. 



Length of centrum in its axis IG lines ; height and breadth in front 14 lines. 

 Length of hypapophysis below the anterior articular concavity of the centrum 

 5 lines. 



Probably the vertebra may belong to the same species as less character- 

 istic fragments of bone, found by Mr. Carter, near Fort Bridger, in the same 

 territory. 



Descriptions of new CRINOIDEA and ECHINOIDEA, from the Carboniferous 

 rocks of the "Western States, with a note on the Genns ONYCHASTER. 



BY F. B. MEEK AND A. H. WORTHEN, 



Of the Illinois State Geological Survey. 



Genus SYNBATHOCRINUS, Phillips, 1836. 

 Synbathocrinus Wachsmdthi, M. and W. 



Body below the top of the first radial pieces nearly semi-globose, or ap- 

 proaching semi-oval, being about twice as wide as high, and rounding to the 

 column below. Base forming one-third to nearly one-half the height, somewhat 

 basin shaped, and obscurely pentagonal in outline as seen from below ; basal 

 pieces, with the two larger divisions wider than high, and hexagonal in outline, 

 and the smaller about as wide as high, and pentagonal in form. First radial 

 pieces two-thirds to three-fourths as high as wide, with a general quadrangu- 

 lar outline, but two of those on the anal side, have each one of the superior 

 lateral angles slightly truncated to form a notch for the reception of the first 

 anal piece, so as to give each an additional angle. Second radial pieces of 

 nearly the same size as the first, but not tapering upward as much as the first do 

 downward, quadrangular in outline, and generally about three-fourths as long 

 as wide. First anal piece about half as wide as long, pentagonal in form and 

 equaling the length of the second radial pieces; second anal piece nearly half 

 as long as the first, on the truncated upper end of which it rests ; trigonal in 

 outline, the upper angle being acute. 



Arms very long and very gradually tapering, angular along the middle of 

 the dorsal side, and each composed of more than thirty quadrangular pieces, 



1869.] 



