BY E. F. KALLMANN. 649 



trichites are mainly confined to the collencliyma, and tlie tricliite- 

 fibres, which are often of very considerable lengtli, occur chiefly 

 along and immediately witliin the boundaries of the same tissue, 

 where it adjoins the choanosome. 



Mastichorions. — The flagellated chambers are nearly spherical 

 and of small size, rarely more than 20/^. in diametex', and situated 

 at an average distance of about 10/a apart. 



Spicules. — Both megascleres and microscleres are precisely 

 similar in form to those of Ji. typica. The former vary in maxi- 

 mum size, in different specimens, from 650 by 7/x to 720 by 9/>(, 

 and their minimum length in any specimen is less than 200//.; 

 individuals below 300/x long, howev^er, are scarce. The trichites 

 are divisible into two groups, the shorter ones varying in length 

 from about 50 to 220/.1, the longer from about 320 to 450/<. 



Genus Desmoxya, gen.nov. 



Definition. — AxinellidteC?) of massive form, typically more or 

 less dome-shajDed, and provided with well-developed, papilliform 

 processes. 8keleton consisting of an irregular, halichondroid 

 reticulation traversed by ascending multispicular, non-plumose 

 fibres. Spongin almost or quite absent. Megascleres of a single 

 order, — oxea, strongyla and styli, differing only in the character 

 of their extremities. Microscleres terminally-spined, arcuate or 

 slightly sigmoidal microxea, and trichodragmata. 



Type-species, D. lunata Carter. 



The single species, for which this genus is proposed, has hitherto 

 been referred to Hiyginsia. The number and importance of the 

 chai'acters distinguishing it from the remaining species of the 

 latter genus, however, render obvious the necessity of its removal 

 therefrom. The structure of the skeleton is essentially the same 

 as in Bhaphoxya, only the main fibres are far fewer, the connect- 

 ing fibres are reduced to a sparse reticulation of spicules, and 

 spongin is almost completely wanting. 



In the several specimens of B. lunata examined by me, the 

 microxea are, without exception, simply bow-shaped, i.e., curved 

 in one plane. In the Austx'alian Museum, however, there is a 



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