206 LIVEEPOOL BIOLOCxICAL SOCIETY. 



referred to by Mr. Higgin under the name Ophlitaspongia 

 seriata, under the genus Clathria, Schmidt. Having found 

 this form in profusion at Puffin Island, April, 1889, and 

 at Port Erin, Easter, 1889 and 1890 (at both places for 

 the first time), I am able to give now a further account of 

 its systematic position. 



I may use the same v^ords in regard to this species 

 which were used by Kidley and Dendy* about Clathria 

 inanchorata: "Although it possesses no chelae, yet this 

 species agrees so closely with the genus Clathria in other 

 respects that we have deemed it advisable to include it in 

 that species, it is perhaps a form that once possessed iso- 

 chelate microsclera and has now lost them." And this 

 Clathria inanchorata is the only Desmacidonid sponge 

 which forms an exception to Kidley and Dendy's defini- 

 tion of the family Desmacidonidse. Their definition runs 

 as follows (page 62): — " Desmacidonidse : Megasclera of 

 various forms, usually monactinal. Microsclera always 

 present and always including chelae." Then they add in 

 a footnote : " We have included one or two species with- 

 out chelae on the supposition that they have had them and 

 subsequently lost them." I would prefer the exception 

 to be included in the definition proper of the family, espe- 

 cially as we do not know whether their " supposition " 

 corresponds to phylogenetic facts. For that reason I am 

 inclined to accept rather Lendenfeld's f definition of the 

 Desmacidonidae : " Cornacuspongiae with a supporting 

 skeleton composed of spiculiferous, often echinated fibres. 

 Generally with cheke in the ground substance. If chelae 

 are absent, the fibres are echinated by projecting spicules." 



* Ridley and Dendy, " Rei)Oit on the Monaxonida collected by H.M.S. 

 ' Challenger/ " p. 150. 



t R. V. Lendenfeld, "Descriptive Catalogue of the Sponges in the Aus- 

 tralian Museum, Sydney," p. 210. 



