Verrill, Notes on Radiata. 2V9 



reticulated with elevated plates and connecting ossicles, as in 0. gig as ^ 

 which bear at most of the nodes or intersections small, conical, naked 

 spines of unequal size, each on a large conical tubercle, which is granu- 

 lated. Around the central area there is a well-marked pentagon, with 

 a large conical tubercle at each angle, corresponding to the rays, 

 and a small one on each side, opposite the interradial region. Within 

 this pentagon there are four spine-bearing tubercles around the slightly 

 convex anal region, and a few others irregularly placed. From the 

 angles of the pentagon a row of large, spine-bearing tubercles, from 

 fifteen to twenty in number, extends along the middle of each ray. 

 The spaces between the reticulations of the upper surface are pierced 

 by very numerous pores, among which there are many small oval pedi- 

 cellariffi. Other similar, but more elongated, pedicellarise are frequent 

 on the spine-bearing tubercles. Madreporic plate small, fine, situated 

 considerably outside of the dorsal pentagon. Color, in alcohol, gray- 

 ish brown ; in life the dorsal plates are bright crimson, the spaces be- 

 tween, greenish brown. 



Panama, two specimens, dredged, in 6 to 8 fathoms, — F. H. Bradley. 



This species is allied to 0. gigas of Florida and the West Indies, 

 but the latter has larger and more numerous spines on the upper 

 surface ; much smaller upper marginal plates, each bearing a conical 

 spine ; more coarsely granulated lower marginal plates ; ventral plates 

 bearing one or two short conical spines ; outer row of interambulacral 

 spines formed by much larger and longer, subacute, stout spines, one 

 to each plate, instead of flat, thin, truncate spines standing two or 

 three to a plate, as in 0. occidentalis. The pedicellarige of the ventral 

 surface are very much smaller and difierent in form, those on the 

 marginal plates are less numerous and more rounded. 



Under the name of Pentaceros Cumingii, Gray has briefly described 

 a very small specimen, which may, possibly, have been the yoimg of 

 this species, but none of the characters given are applicable to our 

 specimens, and the presence of marginal spines in so small a specimen, 

 when they are almost entirely wanting in large ones, is a character 

 which seems to render their identity extremely improbable. 



Gray's description is as follows : " The arms are rather narrow 

 nearly as long as the diameter of the body ; marginal spines few, 

 small ; back rather depressed, with conical protuberances, bearing 

 small spines. Diameter 12". Perhaps the young of a much larger 

 species." 



Punta Santa Elena, rocky ground, 12 to 18 fathoms,— H. Cumino-. 



Crans. Connecticut Acad., Vol. I. 36 April 1867 



