FAUNA OF THE OUTER WESTERN AREA OF THE CHANNEL. 301 



(D) From Irish Sea southwards. 



Xantlio tubcrculatus. (Including Bay of Biscay, Coast of Portugal, 

 N.W. African Coast and Cape Verde Is.) 



Bathynectes longipcs. (Including Channel Is., Mediterranean, Adriatic, 

 and Black Sea). Frequent at Plymouth in recent years. 



(E) From English Channel to Azores. 

 Clathrina contorta. (Including Mediterranean.) 

 Rhizaxinclla elongata. (Including Mediterranean.) 

 Polymastia agglv.tinans. 



(F) English Channel and Adriatic. 

 Grantia capiUosa. 



PORIFERA. 



Calcarea. 



CLATHRINIDAE, Minchin. 



Clathrina coriacea (Fleming). 



One small specimen on a dead Pcctcn shell, at Position 33. 

 Depth, 42 fath. 



Clathrina primordialis (Haeckel). 



At Position 34, one, on shell of Fusus, occupied by Eupagurus. 



Greatest measurement 9 mm. 



„ 38, one, on tube of Pallasia „ „ 10 „ 



„ 45, one, on Inachns 



,, 59, two, on dead valve of Pcci!e?i „ „ 10 „ 



„ 62, one, on Volsdla „ „ 4 „ 



Depth 42-50 fath. 



These five small specimens which I have assigned to Haeckel's 

 Ascctta primordialis show a good deal of individual variation. The 

 habit of growth is in every case that of a simple network of anastomos- 

 ing tubes, with a few short oscular processes, forming a thin investment 

 on the object of attachment. The skeleton is composed almost entirely 

 of equiangular triradiates with the component rays often of slightly 

 unequal length. The size of the spicules is fairly uniform in individuals, 

 but between different individuals the average dimensions of the spicular 

 rays range from about 65/^* in length by 6'5/x in width at base of ray, 

 to about llOyU in length by 10/a in width. The rays are gradually 

 tapered to a rather sharp or sometimes a somewhat blunt point, the 

 tapering being more strongly marked in the distal half of the ray. In 

 one specimen (Xo. 240), the rays are more linear and almost coriacca- 

 like. In two specimens the skeleton is entirely composed of triradiates. 



* The sign /x is used to designate "OOl mm. 



