﻿452 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 102 



Schizostella seems to be most closely related to Asteroporpa^ espe- 

 cially to the group of species including lindneri of the Caribbean, 

 m'straliensis of Australia, and hadracantha of Japan in which the 

 double bands of hook -bearing tubercles on the arms are bordered on 

 each side by a regular row of contiguous enlarged granules, the quad- 

 ruple bands composed of enlarged and hook-bearing granules are only 

 slightly elevated above the general surface of the arms, and the hooks 

 are small, usually without an accessory tooth. In spite of the forked 

 arms it is less closely related to Ash^ocnida, and much less closely to 

 Astroclon. 



In several ophiurans in different families the young have six or 

 sometimes seven arms and reproduce by fission, giving rise to adults 

 with usually five arms. But Schizostella cannot be the young of any 

 known West Indian species as it differs from all related species in 

 details of its structure and ornamentation. 



Although a number of species in several genera of the Trichasteridae 

 are known to reproduce by fission when young, this is the first case 

 to be reported in the Gorgonocephalidae. 



SCHIZOSTELLA BIFURCATA, new species 



Plate 40 



Description. — The disk is 4 mm. in diameter and is composed of 

 seven triangular segments elevated in the middle and with rounded 

 outer angles which are separated from each other by rather deep 

 grooves, becoming deeper outwardly and ending at a deep notch in 

 the interradial border. The seven segments each contain two radial 

 ribs, but appear as single units, seldom giving any indication of a 

 double structure. 



The disk is densely covered with hemispherical granules, the smaller 

 brownish and the larger white, which are irregularly arranged except 

 at the distal ends of the segments, where there are two regular rows 

 of white tubercles separated by two rows of hook-bearing tubercles. 



The seven arms are at the base very nearly as broad as the distal 

 width of the disk segments. They are roughly twice as long as the 

 diameter of the disk and bifurcate at about the middle, on or about 

 the thirteenth brachial. 



The ornamentation of the arms resembles that of the outer part 

 of the disk segments. There are evenly spaced transverse rows of 

 white hemispherical granules between which are double rows of hook- 

 bearing granules alternating with, at the base of the arms, irregular 

 double rows of larger, lower, polygonal granules which farther out 

 become single irregular rows and disappear almost completely at the 

 arm tips. The hooks are minute, very stout, thick-crescentic, without 

 an accessory tooth, and become very prominent on the slender arm 

 tips. 



