ECHI NODE RMS. 71 



The specimens of this species described as females have some resem- 

 blance to H. cavernosus, A. Ag.* {Tripylus cavernosus, Phil.), from Pata- 

 gonia, which is the nearest allied form hitherto described. The latter 

 differs, however, in its pentagonal or elliptical form, less emarginate 

 in front, the anterior ambulacrum being but slightly sunken ; in having 

 the anal area elliptical and pointed at both ends ; the peripetalous fas- 

 ciole less angulated laterally ; the tubercles of the lower surface larger, 

 etc. 



The specimens regarded as males resemble to about the same extent 

 JT. australis, A. Ag.t (Phil, sp.), also from Patagonia. The latter differs 

 in being scarcely emarginate anteriorly and not cordate, in having the 

 fasciole less angulated laterally, etc. The two forms from Patagonia 

 differ one from the other in the same way as do the two supposed sexes 

 of H. cordatus described above, so that, if my view be correct, the two 

 forms described by Philippi will prove to be only the two sexes of one 

 species for which the name australis would be the most appropriate. In 

 S. cavernosus the genital pores are large, and the lateral ambulacral 

 grooves are deep. In R. australis the genital pores are small, and the 

 ambulacral grooves shallow. It is also probable that the sexes may 

 differ in a similar manner in other related genera. 



ASTERIOIDEA. 



ASTERiAS RUPICOLA, Verrill, s. u. 



A small species, with five short, broad, rapidly tapered rays, but little 

 longer than the radius of the disk. Disk rather thick and swollen, rela- 

 tively large. Rays swollen, convex above, flat below, broad at base, 

 where the breadth is often equal to half the total length, measuring 

 from the mouth. The longer radius is from two to two and a half times 

 as great as that of the disk. The ambulacral furrows are broad, with 

 very numerous, closely crowded, slender sucker-feet. The grooves are 

 bordered by a single and very regular row of slender, slightly clavate, 

 obtuse adambulacral spines, which are generally spread outward from 



• Eevision of the Echini, part iii, p. 587, pi. XXI<=, figs. 1 and 2, 1873. 



tOp. cit., p. 586, pi. XXI<=, fig. 3. It is proper for me to state that after the above 

 description was in type, Mr. A. Agassiz, to whom I had sent a specimen of each of the 

 forms for examination, wrote to me that he thinks them identical respectively with the 

 two species of Philippi here referred to, notwithstanding the differences noted. I have 

 thought it best, however, to keep them separate until a larger series of specimens of 

 the American species can be studied. 



