56 



BULLETIN 64, UNITED STATES NATIONAL MUSEUM. 



resembling the supports or feet of the culinary utensil called "skillet" from which is 

 derived the name of cacabs (cacabus). The superior rim is cut out with ten semi- 

 circular apertures for the arms. The whole surface is corrugate with sharp wrinkles. 



Pelvis [base] funnel shaped, pentagonal, divided into five. These pelvic [basal] 

 plates are irregular elongated hexagonal, and line the sides of the funnel shaped 

 cavity which, in the specimen here described, is about 2 cent. met. deep and has a 

 diameter of 15 mil. m. at the top and 4 mil. m. at the bottom consequently it is an 

 inverted truncated pyramid giving to these plates an elongated triangular appear- 

 ance. These pelvic plates show only a very small part on the surface of the cup; 

 merely a straight edge having both extremities beveled — these bevels forming with 

 those of the next adjacent pelvic plates a reentering angle. Upon the above men- 

 tioned straight edge rest five — 



Costals [radials] — they are short, pentagonal, very much elevated in the centre, 

 presenting a prominent tubercle as stated above, the superior salient angles sup- 

 port five — 



Scapulars [primibrachs], are longitudinally compressed hexagonal plates, two 

 parallel sides forming the lateral margins, one of the angles forms the apex while the 

 opposite angle forming the base is a re-entering angle — this re-entering angle is filled 

 by the superior angle of the pentagonal costal [radial] while the superior, a salient 

 angle, supports two irregular pentagonal plates, which are followed by two similar 

 ones, and terminate in two arms, having circular apertures round the rim. 



Five inter-costals [interbrachials] of an elliptic form, rendered more or less angular, 

 by the adjacent plates, or they are polygonal rendered elliptical by the corrugation — 

 they fill up the re-entering angle mentioned above and are surrounded on both sides 

 by the costals [radials], scapulae [primibrachs], and by the plates which rest upon 

 the hexangular scapulae and support two elongated hexagonal inter-scapulae [sec- 

 ond interbrachials]. 



Inter-scapulae [second interbrachials] 10, of an elongated hexagonal form — they 

 support first two small plates, upon which follows a row of four still smaller plates; 

 upon these follows a horizontal beveled edge filling the space between two apertures 

 for the arms and completing in this manner the superior rim of the cup. 



The capital integument as well as could be discovered from my imperfect speci- 

 men, is formed of polygonal plates of which the form could not be ascertained, they 

 are carved somewhat similar to those of the cup. — No oral [anal] aperture is visible, 

 it existed probably on the part that is destroyed. 0 Around the margin, between 

 two arms and between each pair of arms [radi] are series of elongated pores — between 

 two arms generally five, and between each pair of arms seven, these numbers vary, 

 nevertheless the number between each pair is always the largest. 



Observations. — Could Troost's description have been published at 

 the time it was presented this fine specimen would have been the 

 type of the genus, but, as shown by the synonymy, Hall's publication 

 of the diagnosis did not appear until 1862, and the species also has 

 been described by others. 



This species is closely related to Dolatocrinus excavatus Wachsmuth 

 and Springer, but according to the descriptions it differs in having 

 8 to 10 pores between the arms while the latter has 4 to 6 pores. 



« Since the above description was drawn up, I have seen a specimen of this fossil 

 in the collection of Doctor L. P. Yandell which has its capital integument more com- 

 plete than my specimen, from which it appears that it is covered with numerous 

 small polygonal plates in the form of a- dome having a central oral [anal] aperture 

 surrounded with a few small plates, slightly elevated above the general level. 



