494 Transactions of the Society. 



by mechanical means, I subjected a portion of the coral bearing one 

 to the influence of acid, when the papilla above mentioned was not 

 only eliminated in a perfect state, but numerous brown points 

 made their appearance at various depths from the surface of the 

 coral, which, as the latter became entirely dissolved by the acid, 

 were, together with the cribrate papilla, found to be processes of 

 membranous, cellular sarcode, presenting a brown colour (in its 

 dried state), which lined the centre of the coral, now reduced by 

 excavation from solidity to a mere shell in many parts. These 

 ' processes ' which were conical and thus engaged in excavating the 

 coral, might also, on reaching the surface, grow into the form of 

 cribriform papillae if necessary. 



"As the sponge appears to be nearly allied to Gummina 

 Wallichii* recently described and illustrated by Mr. Carter, which 

 he informs me has therein by mistake been called ' Corticium,' 

 I do not think I can do better than hand it over to him for 

 technical record." 



Having thus premised Dr. Millar's remarks on his discovery, 

 I now proceed to comply with his request. 



Alectona \ Millari, Crtr. n. sp. 

 Amorphous, excavating, membranous, cellular, consisting of 

 simple, fibreless sarcode (now, i. e. in its dried state, brown and 

 gum-like), charged with the spicules of the species and projecting 

 outwardly, in processes of different forms and different degrees of 

 length, until some reach the surface, where they appear like flat- 

 tened papillae. " Processes " of two kinds, viz. those which form 

 papillae on the surface, which are comparatively large, and those 

 which extend more or less into the substance of the coral, which 

 are minute. Papillary processes of two forms, viz. one with an 

 irregularly circular, more or less flattened, cribrate head, in which 

 the spicules of the species, imbedded in sarcode, produce a cribri- 

 form structure dividing the area of the head into a variable 

 number of minute apertures, each of which in all probability, when 

 fresh, is provided with a delicate sphinctral diaphragm of sarcode 

 (PI. XVIIa, Figs. 1 and 2) ; and the other, with a conical head in 

 which the spicules are arranged radiatingly, so that when retracted 

 in the living state, a single large aperture only would be presented. 

 Each form of the papilla when largest, about gV iiich in dia- 

 meter, but variable, down to ■^'^^ inch with holes in the latter 

 correspondingly small, viz. t-sVt7 to TSTio inch in diameter. 

 Minute conical processes or points engaged in excavating the coral, 

 but all charged to the extremity with spicules of the species, 



* ' Ann. and Mag. Nat. Hist.,' vol. iii. 1879, p. S.^S. 

 t Alecto, one of the Furies. 



