126 HAWAIIAN AND OTHER PACIFIC ECHINI. 



Subanal rostrum more or less well developed. 



Subanal rostrum small, overhung by test; no subanal fasciole Spatagocystis. 



Subanal rostrum conspicuous, not overhung by test; subanal fasciole present. 

 Test stout, not greatly elongated; dorsal plates of interambulacrum 5 alter- 

 nating; often 2 pores in plates Ial and Vbl 



Test widest anteriorly; 1 or 2 pores in Ial and V61 Ceratophysa. 



Test not widest anteriorly; only 1 pore in Ial and V£l Helgocystis. 



Test not stout, more or less elongated; dorsal plates of interambulacrum 5, 

 paired; only 1 pore in Ial and Vbl. 



Bivial ambulacra discontinuous; test not excessively elongated . . . Pourtalesia. 

 Bivial ambulacra continuous; test excessively elongated Echinosigra. 



Sternopatagus. 



De Meijere, 1902. Tidj. Ned. Dierk. Vereen, (2), 8, p. 10. 

 Type, Sternopatagus sibogae de Meijere, 1902. hoc. cit. 



The Siboga took a single specimen of this interesting form south of Timor 

 in 1139 fms. No other specimens have since been met with. 



Echinocrepis. 



A. Agassiz, 1879. Proc. Amer. Acad., 14, p. 206. 

 Type, Echinocrepis cuneata A. Agassiz, 1879. hoc. cit. 



Like most of the genera in this family, Echinocrepis is monotypic and our 

 knowledge of the species is limited to very scanty material. Two specimens 

 were taken by the Challenger in 1610 fms. near the Crozet Islands, but one 

 of these appears to have been lost, for there is none in the M. C. Z. collection 

 and Mortensen states (1907. Ingolf Ech., pt. 2, p. 83) that there is only one 

 in the British Museum. 



Cystocrepis. 



Mortensen, 1907. Ingolf Ech., pt. 2, p. 84. 

 Type, Echinocrepis setigera A. Agassiz, 1898. Bull. M. C. Z., 32, p. 78. 



Plate 145, figs. 1, 2. 



Mortensen's reasons for separating from the Crozet Island species, the 

 Panamic echinoid placed in Echinocrepis by Mr. Agassiz. seem adequate. In 

 his description of the pedicellariae, he refers to three kinds, trident at e. rostrate, 

 and ophicephalous. I find the same three kinds but should call them triphyllous, 

 tridentate, and ophicephalous. The triphyllous or small tridentate are very 



