22 Mr. H. J. Carter on two new Species of Gumminese. 



sufficient : we want to know if they take in crude material for 

 food, like those of the other sponges. This is what I claim to 

 have shown in 1857 in Spongilla (Annals, vol. xx.), and re- 

 peated in 1871 in Grantia compressa (ib. vol. viii.). 



The birotulate of Corticium abyssi is the smallest spicule 

 that I have met with. Even under l-40th-inch focus, which 

 Mr. Powell, junior, kindly put upon it for me, I could hardly 

 distinguish its form, and then not so distinctly as with one of 

 his ^ immersion object-glasses. (So much for the definition of 

 the higher powers !) To see this spicule, even tolerably satis- 

 factorily too, with a ^, it is necessary to boil a piece of the 

 Corticium in nitric acid, and, after a convenient amount of 

 dilution with water, to place a little of the fluid containing the 

 spicules under a glass cover, when, by the vibration of the 

 spicule causing it to turn over and over, the arms may now and 

 then be distinguished, and the shaft appear to be microspined 

 about the centre. This must be done at once, as the accumu- 

 lation of organic matter about the spicules, after a few hours' 

 interval, entirely defeats the object. 



One of the most interesting points elucidated by the exami- 

 nation of this deep-sea specimen is the fact that the Corticium 

 has enveloped the remains of a Farrea, and that the Corticium 

 possesses similar " biternate " spicules to those figured by Dr. 

 Bowerbank as the " retentive spicules " of his Farrea occa 

 (Proc. Zool. Soc. Lond., May 18G9, pi. xxiv. figs. 2-6). 



Were it not evident that a " biternate " spicule can never 

 form part of a Hexactinellid sponge, the fact of such spicules 

 having not only been figured in connexion with Farrea occa, 

 but also with Dactylocalyx pumiceus and Ip>hiteon panicea 

 (Proceed. Zool. Soc, Jan. 1869, pi. iii. fig. 16, and May ib. 

 pi. xxii. fig. 11), would cast a doubt over their real parentage. 



Taken, however, in connexion with the fact that Dr. Bower- 

 bank's specimens of Farrea occa were obtained from the detri- 

 tal mass supporting Euplectella cucumer, Owen (Trans. Linn. 

 Soc. vol. xxii. pi. xxi.), it seems not unlikely that they were 

 there also accompanied by a Gummina, as in our deep-sea 

 specimen, but of a form, as may be seen by the spicules figured 

 by Dr. Bowerbank, still more nearly approaching those of 

 Schmidt's Corticium candelabrum (op. cit. Taf. iii. fig. 25, a,g) 

 than those of Corticium abyssi. 



The fragments of Farrea enveloped by Corticium abyssi in 

 the deep-sea specimen (fig. 2,dd) will form the subject of my 

 next communication, in which I shall endeavour to show what 

 the ldbse spicules that belong to Farrea really are, and what 

 relation Farrea itself bears to Aphrocallistes. 



