REPORT ON THE HEXACTINELLIDA. 137 



which A. B. Meyer had sent to the British Museum from Zebu, one of the Philippine 

 Ishands, and named it Rossella philippinensis} It was a longish oval specimen as large 

 as a walnut ; its transversely truncated upper end bore the wide round orifice of a deep 

 central cavity, while, from the inferior half of the otherwise smooth body, a cylindrical 

 bundle of long siliceous spicules ran out radially at different distances from one another, 

 and then bent downwards into a tuft. That this sponge belongs to the genus 

 Rossella was confirmed by Carter in a communication addressed to Gray ; the four-armed 

 spicules of the skin with their somewhat backwardly bent branches were to him sufficient 

 proof of the fact. Yet, as Carter remarks, this form may be readily distinguished from 

 Rossella antarctica by the fact that the arms of the outer spicules are smooth, and not 

 beset, as in the latter, with delicate microspines. 



Carter has also directed attention to the great similarity between the spicules of 

 Rossella phiUpinnensis and those found in the genus Crateromorplia, Gray. 



Wy ville Thomson," gave an account of a third species of Rossella, which was dredged 

 in 651 fathoms, to the west of the opening of the Strait of Gibraltar. The oval body of 

 tliis remarkably elegant sponge, described as Rossella velata, bears superiorly (as in 

 Pheronema) a single large round osculum, but instead of forming a cup uniformly lined 

 with a netted membrane, the oscular cavity divides at the bottom into a number of 

 branching passages as in Pheronema annse described by Leidy. 



" A delicate outer veil about a centimetre from the surface of the sponge is formed by 

 the interlacing of the four secondary rays of large five-rayed spicules which send their 

 long shafts from that point vertically into the sponge body. The surface of the sponge 

 is formed of a network of large five-radiated spicules arranged very much as in 

 Pheronema." 



In a paper on Sarcohexactinellidan Sponges,^ Carter has noted that in Rossella velata 

 and Rossella philippinensis "the minute equi-armed hexradiate spicules pass from the 

 equi-armed hexacts with bifurcated and pointed extremities to the same with capitate 

 extremities, and lastly into an unclescribed form where the ends of the arms are terminated 

 by a small conical tuberculated inflation presenting a short straight spine on the apex, 

 which spine is surrounded by almost innumerable linear filaments rising each from one of 

 the tubercles, attaining various heights and bending outward like the expanded petals of 

 a tubular flower, forming one of the most exquisite objects in nature. It might be named 

 ' pappiform' flexed and simple in contradistinction to another kind in which the filaments 

 are straight and capitate." 



The generic diagnosis of Rossella was given by Carter in his Review of the 

 Hexactinellida * in the following words: — "Rosette few- or many-rayed: rays few of 

 equal length straight and pointed or spinocapitate ; or multitudinous, of unequal length, 



' Ann. and Mag. Nat. Hist., ser. 4, vol. x. pp.- 137, 138. " The Depths of the Sea, p. 418, 1873. 



3 Ann. and Mag. Nat. Hist., ser. 4, vol. xi. p. 279. * Ann. and Mag. Nat. Hist., ser. 4, vol. xii. p. 3G1. 



(ZOOL. CHALL. EXP. PART LIII. 1886.) Ggg 18 



