ASTEROIDEA OF NOBTH PACIFIC AND ADJACENT WATERS — FISHER. 237 



The coelomic cavity of a specimen from station 4420 was nearly filled with 

 a large i)arasite, the Ascothoracid crustacean Dendrogaster, a figure of which is 

 given. (PI. Ill, fig. 1.) This specimen has a very weak dorsal skeleton and the 

 hepatic cceca are small. Many of the abactinal plates are disconnected and inde- 

 pendent, a state of affairs which is not found in a normal example. 



Genus CRYPTOPELTASTER Fisher. 



Cryptopehastcr Fisher, Hull. I!iir. Fi.shcricfl for lilO-l, vol. 24, June 10, l!»0.j, [>. :!1I. Type, 

 C. lepidotiotus Fisher. 



Diagnosvi. — Nearly related to Hippasteria, from which it ditTers in having the 

 whole abactinal surface covered with numerous flat, circular, quadrate, oval, elliplical, 

 triangular, and polygonal granules attached to the plates and secontlary intermeiliate 

 ossicles in such a ihanner that there is a very narrow free projecting edge which some- 

 times overlaps the next granule. The primary circular or elliptical abactinal i)late3are 

 spaced, and the small intermediate ossicles are quite independent and not arranged 

 so as to form connecting pieces, as in Ilippasteria. Primary abactinal plates with 

 low central spine or tubercular granule, ami many %vith a largo lowbivalved pedi- 

 cellaria occupj'ing entire width of plate. Actinal and marginal plates covered with 

 fiat large granules similar to those of dorsum, but usually without the free rim. 

 Marginal j)lates with a central short tubercular spine. Actinal intcrradial areas 

 extensive, the intermediate plates adjacent to adambulacrals with large bivalved 

 pedicellarire; the others with one or more enlarged central granules. Adambulacral 

 plates with two heavy furrow spines and one shorter actinal spine, similar in char- 

 acter to those of Hippasteria; but, unlike that genus, the furrow series is often 

 replaced by a large bivalved pedicellaria, occupying entire length of furrow margin. 



Remarks. — There are three features in which this genus differs from all species 

 of Hippasteria — the character of the granulation, the arrangement of the abactinal 

 secondar^- plates, and the substitution of a large bivalved ])edicellaria for the 

 furrow s])ines on some of the adambulacrals. The last I do not consider as of so 

 great importance as the first and second. In this genus there is no indication of the 

 abactinal membrane which is always more or less evident in Hippasteria an<l in 

 which the granules are immersed. Sometimes this membrane is thick and com- 

 pletely hides the underlying plates (as in //. heathi); it always forms a thin coating 

 on the granules. In Hippasteria the granules form a border about the larger jilates 

 of the abactinal surface as well as surrounding the marginal plates, t^ven the 

 intermediate plates are defined by a marginal series of granules. In Cnjptopeltaster 

 the entire surface is covered with Hat valve-like granules, ami the intermetliate 

 ossicles usuallv bear but one large flat valve, like the flaring head of a nail. It is on 

 the intermediate plates that the free edge of the granule is most evident. 



Lutlwig (190.'), p. 140) has indicated that the disposition of the abactinal 

 secondary intermediate plates of his parifica (which he figures) is not unlike that of 

 Hippasteria phn/giana. I have examined the dorsal skeleton of two specimens 

 of the latter species and find that the intermediate plates act as binders or joiners of 

 the primary plates. The character of the dorsal skeleton is the same as in //. spinosa. 

 and quite unlike that of Cniptopeltanter. where the intermediate plates do not in any 

 way coiuicct the primary dorsal jdntes. 



