403 COLLECTIONS FROM MELANESIA. 



Surface cvon, very slightly roughened by the projecting primary 

 skeleton-lines, which form a fine velvet-like pile. Texture in spirit 

 soft, compressible, clastic ; colour pale brown, with a slight (possibly 

 accidental) tinge of purple. Main skeleton — network rectangular ; 

 fibre to the eye wholly composed of spicules loosely aggregated, 

 especially in the secondary fibres ; primary fibres running at right 

 angles to surface, spicules 3- to 5-serial ; secondary fibres, spicules 

 1- to 3-serial; intervals between primaries about '17 millim., and 

 the same between secondaries. No special dermal skeleton. Sarcode 

 dark umber-brown. Spicules smooth acerate, slightly and gradually 

 curved, tapering gradually to sharp points from near centre; size 

 •21 by -Oil millim. 



Hob. West Island, Torres Straits, 7 fms. ; bottom mud and 

 coral. 



Distribution. St. Peter and St. Francis Islands, Australia 

 (Lamarck). 



The " leviter incrustae fibrae " and the " 2- seu 3-fidi tubuli " of 

 Lamarck's description are the only points not quite in agreement 

 with our specimen ; but it is evidently young, and might have 

 branched when older ; and the " incrustae " apparently alludes to tho 

 sarcode, which here, as in Lamarck's var. ficlis subnudis, has not all 

 been retained ; his specimens were 18-25 centimetres (7-10 inches) 

 in length. Schmidt's Reniera alba (Adr. Meer. p. 73), from tho 

 Adriatic, seems to resemblo the species, but a umserial network is 

 figured for its skeleton. 



"& 



39. Reniera ferula. 



Isodictya ferula, Boicerbank, Man. Brit. Spong. iv. p. 11G, pi. viii. 

 figs. 1-3. 



A small specimen of the size and shape of a hazel-nut, with few 

 vents about *8 millim. in diameter : colour (in spirit) dull brown. 

 It does not bear the interesting handle-like process on which 

 Dr. Bowerbank lays so much weight as a " caudal appendage," 

 which is (as the type specimens appear to have been young) perhaps a 

 form of a stolon, like that described by Mereschkowsky in an Esperia 

 from tho White Sea (Mem. Acad. Petersb. xxvi. no. 7, p. 22, pis. i. 

 & iii. figs.), but which, as being apparently sessile by its whole 

 length, as a stolon would normally be, Dr. Bowerbank cannot be right 

 in comparing (I. c. p. 117) with the erect digitate processes which 

 distinguish the genus Polymastia. The absence of this lobe does 

 not appear to be of sufficient importance to separate this specie- 

 from Bowerbank's. The spicules measure *21 by *0079 millim., 

 whereas those of Bo werbank's type specimen are •]!) by -0] millim., 

 and are thus decidedly stouter ; the arrangement of the skeleton is 

 essentially the same in both species. The specimen is attached to 

 what seems to be a Hydroid stem. 



Hab. Port Darwin, 7-12 fms. ; bottom sand and mud. 



Distribution. Ireland (Bowerbank). 



