I ^h "ENDEAVOUK" SCIENTIFIC RESULTS. 



(ii.) 1 he amphiastersl bear at either end a terminal whorl of 

 about six to eight rays which stand almost perpen- 

 dicularly to the shaft or are directed forwards at a 

 small angle (up to 30°, sa}). The width of the spicule, 

 between the tips of the rays, measures from about 

 three-fourths of, to slightly less than the length of 

 the spicule, which is rarely as much as 5 p. 



Loc. — Coast of Xew South Wales, eight miles east of San- 

 don Bluffs, 35-40 fms. ("Endeavour.") 



Family DKSMACIDONID.-E. 

 Whether the Desmacidonida? be di\ ided into two sub- 

 tamilies, Mycalinae and Ectyoninte, in the usual way; or 

 whether, in accordance with Topsent's proposal, the Myca- 

 lina? be sub-di\ided so as to yield an additional sub-family, the 

 Dendoricince — the result, if a natural grouping of the genera 

 be our aim, is not altogether satisfactory. Of the two, Top- 

 sent's classification is the better since, with very few excep- 

 tions as their microscleres show, the genera which remain in 

 the Mycalina' after the removal of the Dendoricina? stand well 

 apart from the rest of the family. The main fault lies in the 

 artificiality of the distinction upon which the separation of the 

 Ectyonina? and Dendoricina,' is based. Species are placed in 

 one or the other of these sub-families according as spicules of 

 one particular kind — the accessory spicules — are present or 

 absent, whilst no value at all is placed upon the presence or 

 absence of the equally important "skeletal" and "dermal" 

 spicules, nor any notice taken of the plain indications afforded 

 bv the microscleres. As a consequence, we have closely allied 

 if not almost identical genera like Ectyuuioryx and Lissoden- 

 doryx, Ectyomyxilla and MyxiUa, Pocillon and loplion, Hyme- 

 trochoia and lotroclwta placed, the one in the Ectyoniuce, the 

 other in the Dendoricince, whilst on the other hand wholh' un- 

 related species like those of JJllsoneUd and (laihria are put in 

 a single genus without question or comment. L'nder these 

 circumstances there is no ad\ antage in maintaining these sub- 

 divisions, and I propose therefore to merge the Dendoricir!.'t^ 

 and Ectyoninae in a single sub-family, to be called the Myxil- 

 lina?. It is probable that the Myxillinse are capable of sub- 

 division into two fairly natural groups in the way suggested 

 below, but on this question I prefer to reserve judgment. I 

 vvould, however, \enture the opinion that the iM}xillin;i; are 

 derived from a single stem distinct from that from which the 

 great majoritv of the Mycalinje have sprung, and from this 

 point of \iew will enter upon a brief discussion of the sub- 

 familv. 



1 Not having succeeded in making out the details of the structure of 

 this spicule, I have not attempted to figure it. The rays appear to be 

 often bifurcate and to have at times a slightly tuberculated surface. 



