NEW GENERA AND SPECIES OF ECHINODERMATA, 



BY S. A. MILLER AND WM. F. E. GURLEY. 



SUBKINGDOM ECHINODERMATA. 



CLASS CRINOIDEA. 

 ORDER CYSTOIDEA. 

 FAMILY HOLOCYSTID^. 



HOLOCYSTITES GYRINUS, n. sp. 



Plate I, Fig. 1, ventral view; Fig. 2, posterior view; Fig. 3, 



summit view. 



This species is large, and if the almost perfect specimen, which 

 we have illustrated, possesses the normal form of complete de- 

 velopment, then it became free in the later stages of growth, for 

 a scar at the terminal point, indicates an attachment to some 

 foreign object in a younger state. The specimen is a little de- 

 pressed dorso-ventrally. It is broad and rounded at the summit, 

 followed immediately below by a sac-like swelling, from which it 

 is continued in an obconoidal form until it terminates in an ob- 

 tuse point. The fanciful resemblance, in the general outline, to a 

 tadpole suggested the specific name. 



Commencing at the base or lower end, there is a solid obconoidal 

 piece nearly as long as its greater diameter, which is followed by 

 a range of eight unequal, irregular, and more or less elongated 

 plates. Two plates are inserted between this range and the next on 

 the right part of the ventral side. There are eleven large and elon- 

 gated plates in the second range, and three plates are inserted on 

 the posterior side, between it and the next range. There are thirteen 

 large, irregular and elongated plates in the third range and nine- 

 teen plates in the fourth range. The fifth range consists of plates 

 more irregular in their order of arrangement and still more 



