﻿146 'ENDEAVOUR" SCIENTIFIC RESULTS. 



also, one is inclined to refer: Mesapos, Tethyspira, Hymer- 

 habdia and Cerbaris (which appear to be lacking in auxiliary 

 megascleres) on account of the analogy which their spicules 

 bear to principal and accessory spicules ; Echinochalina, which 

 seems to be related to Echinoclathria; Stiberotelites, regarded 

 by Topsent as allied to Plocamia ; and the aberrant genus 

 Agelas (including Ectyonopsis) the aflfinities of which appear 

 to be rather with the toxa-bearing Myxillina-. On the other 

 hand, one would assign rather to the latter group : Pscudo- 

 clutliria, which presents some analogies with GraycUa; Stylo- 

 tellupsis, on account of its resemblance in many respects to 

 Clatlirissa; and (necessarily) Tylosignm, because of its sig- 

 mata. 



A few genera still remain to be accounted for, the position of 

 which is not quite clear ; but suflficient has been adduced, I 

 think, to indicate the feasibility of such a subdivision of the 

 Myxillina,' as has been suggested. It is clearly evident, how- 

 ever, that no wholly satisfactory grouping of the species and 

 genera of the Desmacidonidce can be arrived at, until other 

 characters, in addition to those which the spicules afford, are 

 taken into account in classification. 



Genus Clathrissa, Lendcnfeld. 



1888. Clathrissa^ Lendenfeld, Descr. Cat. Sponges, Austr. 

 Mus., 1888, p. 217. 



The genus Clathrissa was introduced by Lendenfeld for 

 three Port Jackson sponges which he named C. arbuscida, 

 C. elegaiis, and C. pumda respectively; of these, the first 

 mentioned possesses chief claim to be regarded as the type- 

 species, and is here so considered. They were defined as 

 "Desmacidonidai with a skeleton composed of dense bundles 

 of slender oxea with very little spongin, echinated by spined 

 styli." Concerning the precise nature of C. elegans, nothing 

 can be said with certainty, since in the existing collection of 

 the Museum, no sponges identifiable as such have so far been 

 met with. An examination of the type-specimens of the other 

 species shows that in both the structure of the main skeleton 

 is similar to that of Pluviohalicliondria, and that microscleres 

 are present in the form of chelae arcuatae. In C. puntila, 

 however, there is, in addition, a dermal skeleton of acantho- 

 styles, so that this species belongs to the genus Crella. The 

 other, C. arhnscida, agrees essentially with many species at 

 present included in Flumohalichondria , viz, those with arcuate 

 chelae. If, however, the microscleres of P. microcionides (the 

 type of Plumohalichoruhia) be ancora% as Thiele's figures of 

 the spicules of P. nepluni^ and his statement concerning the 



• Thiele— Archiv. Naturg., 1903, i., Heft 3, p. 387, pi. xxi.. fig. 19. 



