12 Porifera. 



small branches of afferent and efferent canals open into spheroidal flagellate cham- 

 bers ; the oscula are usually on papillae. Tedanione n.foetida n. differs from Tedania 

 in oxeote spiculation. 



Weltner ( 2 ) notes the frequent presence of Sisyra and other larvae in freshwater 

 sponges, and gives popular instruction. 



Garbini finds Euspongilla in lake Garda not to assume the branching form said 

 to be characteristic of still waters. Chlorophyll corpuscles are partly endogenous, 

 partly parasitic algae of probably various species. Figures illustrate Leptocems 

 spongillae with its protective tube of spicules and living sponge tissue ; a list of 

 parasites and symbionts is given with a summary of Spongillid distribution. 



See also Traxler aud Barrois. 



3. Calcarea. 



See also Hanitsch( 1 ), Herdman, Lendenfeldf 1 ), Topsent( 3 , 5 ), Vosmaeri 1 ), 

 Weltner I 1 ) and supra p 5 Masterman(V 2 )> P 5 Bidder, p 11 Topsentf 2 ). 



Dendy finds that the tuning-fork spicules in Lelapia australis [see Bericht f. 

 1892 Porif. p 9] form long fibres; they seem held together by the gelatinous 

 ground substance of the mesoderm, without any special substance analogous to 

 spongin, and are so closely packed that individual spicules are difficult to distin- 

 guish. The fibres are not so large as the huge oxeote spicules, the strength of 

 the skeleton does not therefore depend on them: they run in every direction, but 

 mostly obliquely from gastral to dermal surface, the basal rays of the spicules nearly 

 always point to the dermal surface and the fibre frequently arises from the basal 

 ray of a subgastral triradiate. They are probably derived from the articulate tubar 

 skeleton of a Syconoid ancestor. The canal-system isLeuconoid; L.\s probably 

 an offshoot from the Leucandra branch of the Grantidae. We require further know- 

 ledge of the fossil Pharetrones to say if any of them are genetically allied; the 

 family is not necessarily a natural one ; but the fibrous skeleton cannot now be 

 considered impossible to derive from that of the existing families. 



Hanitsch ( 2 ) defines Amphiute n. Paulini n., having longitudinal oxea in both 

 gastral and dermal surfaces. 



