6P0XGIIDA. 379 



and non-rectangular arrangement with those of Euspongia, and, as 

 stated already, foreign bodies are the exception even in the surface- 

 tufts; the diameter of the fibres is "4 to •? millim. | Ehlers gives '5 

 to '8), except in the delicate DifeZa-network of the surface and in- 

 terstices, where it is *0085 to "022 millim. Ehlers says that the 

 fibres contain ;i in der Axe vereinzelte Behx diinne spitz-spitze 

 Nadeln (0*1 mm. lang, -006 nun. breit ) welche nur in den kegel- 

 formigen Zuspitzungen an der Oberflache des Schwanimes etwas 

 dichier gehauft sind."' Their occurrence singly (/'vereinzelte") and 

 not in longitudinal series, if that is what is implied, is not the usual 

 mode of occurrence of spicules in the fibres of Chalinidse (though it 

 occurs occasionally in some fibres of Cladochalina >, nor is their 

 greater abundance in the surface-tufts, so far a> I know, usual in 

 this family. These statements appear to me to point towards the 

 true explanation of the nature of these spicules, viz. that they are 

 foreign, and taken in (as is usually the case in Euspongia) as foreign 

 bodies in small quantities into the surface-tufts. A re-examination 

 of the original specimen is desirable. If Esper's species is a C'halinid, 

 then the present species is a j^wspongria-isomorph of a C'halinid form, 

 like the Chalinopsid representatives of riipho nucha I'm a and I'achacha- 

 lina which Schmidt (Spong. Meerhusen Mexico, p. 80) has described 

 as Siphonochalinopsis and PachycJialiiiopsis. 



I have satisfied myself that another explanation which might be 

 suggested, viz. the dissolution of the spicules from the fibre of the 

 Sponge (as in Carter's Aplysina chalinoides, afterwards found to 

 be a true Chalinid), cannot apply to this case. I have studied 

 the fibre very carefully, with and without the aid of potash, and can 

 assert that it never possessed "proper'" spicules. 



The respective localities (Cape and Torres Straits) perhaps con- 

 stitute relative objections to the specific identity of the present with 

 Esper's species. 



Hah. West Island, Torres Straits. 



Distribution. Esper's species is from the Cape of Good Hope. 



3. Euspongia officinalis, Linne, var. cavernosa. (Plate XLI. fig. g.) 



Erom a depth of 10 fathoms in Torres Straits we have a small 

 turnip-like sponge, unfortunately preserved only in the dry state, 

 which to the unaided eye presents the general appearance of a Ehi- 

 zochalina fistulosa, with several tubular processes, 10 to 35 millim. 

 long and 8 to 10 millim. in greatest median diameter, on its upper 

 surface ; these processes are, however, ragged in outline at their 

 distal ends, and evidently in life opened through the fringed aper- 

 ture, now obscured by the falling together of the sides ; their sides are 

 in some cases fenestrate. The body of the sponge is rudely globular, 

 and is drawn up above into monticular elevations, which are termi- 

 nated by the tubes just described ; the base is somewhat flattened, 

 and has apparently been attached at three points to rock or gravel at 

 the sea-bottom, portions of which are still left imbedded in the sponge. 

 The chief horizontal diameters of the sponge-body are 15 and 55 



I 



