Mr. T. Ili^'^in on some Curihhran Sjxnujius. 295 



stellate .sj)ieule.s to the erect spoiij^e. Only one patch of this 

 sponge, liowever, coultl be discovered, though it must have 

 been abundant in the neighbourhood, and may have existed 

 in quantity on the nuUipore, but had been removed by 

 cleaning ; the one example of the species remaining, however, 

 is so far uninjured and undisturbed that its original form and 

 mode of growth can be easily observed. 



It consists, in its dried state, of a thin layer of sarcode very 

 densely charged with stellate spicules, whose rays are smooth, 

 pointed or spino-capitate respectively (figs. 6 and 7), while 

 the surface of the sponge bristles with the pointed shafts of 

 erect, long, spinulate spicules arranged separately but near each 

 other, with their large ends imbedded in the sarcode amongst 

 the stellates. The spino-capitate rayed spicules are half the 

 size of the smooth pointed or conically rayed ones, which 

 measure rather more than O'OOl inch, rays included ; and the 

 spinulate spicules, which are subterminally inflated, are in 

 their largest forms 0*02 or 3V- "^ch in length by jVou inch 

 in diameter. 



The spiculation of this sponge denotes its relationship to 

 the Suberitida, in which family there is less hesitation in 

 placing it since Mr. Carter has expressed tlic opinion (Ann. & 

 Mag. Nat. Hist. 1876, vol. xviii. p. 229) that the spiculous 

 suborder of Carnosa, viz. Gumminida, will eventually be 

 found to pass into the suborder Suberitida, Its forms of 

 spicules respectively indicate a close alliance to those of Tethya 

 lyncnriuin (Johnston), which is also sometimes found lamini- 

 form in growth; and therefore it must be regarded as a species 

 of the genus Donatia{=T. lyncurium) constituted by the late 

 Dr. J. E. Gray (Proe. Zool. 80c. 1867, p. 541). 



As regards spicules a similarity also exists between this 

 sponge and Coluintiitis squamata, Schmidt (Grundzuge einer 

 Spongienfauna des Atlantischcn Gebietes, p. 25, Taf. v. 

 figs. 3, 4), which possesses a subterminally inflated spinulate 

 spicule basally imbedded in sarcode, charged -with globostel- 

 lates with conically pointed rays, and with other stellates 

 whose rays are abruptly terminated ; but it is difficult from 

 Dr. Schmidt's description and figures to recognize any essen- 

 tial difference between C. squamata and the British examples 

 of T. lyncnrinnij which it resembles so closely in its spicula- 

 tion and in the .section of the cortical layer so well seen in Dr. 

 Schmidt's fig. 3. This sponge, therefore, seems clearly to find 

 its proper place in the genus Donatia. 



Its spicules closely resemble those of Mr. Carter's sponge on 

 the crab's claw, the stellates being exactly the same both in 

 form and size ; but the pin-like spicules of Mr. Carter's sponge 



21* 



