176 On the Suhnarine-Cahle Fauna. 



PORIFERA. 



Small fragments of a sponge occurred on the stems of a 

 zoophyte. Not recognizing it, I forwarded it to Dr. Bower- 

 bank, who pronounced it new, and has characterized it as 

 below. There w^as also a mass of siliceous root- fibres, re- 

 minding one strongly of those of HoUenia Carpenter i ; but 

 they are not referable to that species, inasmuch as there were 

 no liamatc spined spieides {vide Thomson's plate Ixviii. fig. 5), 

 and the simple spicules were of two sizes — the one nuieh larger 

 than those of //. Carpenteri, the other very much more slender. 

 I am not able, therefore, to refer this " beard " to any known 

 sponge. I should add, however, that Dr. Bowerbank thinks 

 they belong to Iloltenia ; but I cannot agree with him, for the 

 reasons I have stated, in thinking so. 



^^Isodicti/a Junalis, Bowerbank, n. sp. 



" Sponge massive, sessile. Surface smooth, but uneven. 

 Oscula simple, dispersed, minute. Pores inconspicuous. 

 Dermal membrane pellucid, spiculous ; tension-spicula aceratc, 

 slender, subfasciculate, rather few in number ; retentive spicula 

 bi- and tridentate equianchorate, rather few in number, and 

 rarely palmato-tridentate equianchorate ; also simple and 

 contort bihamate spicula, minute and very slender, rather few 

 in number. Skeleton : spicula acuate, stout, rather short, 

 basally incipiently spinous ; primary lines tri- or quadrispicu- 

 lous, rarely more ; secondary lines mostly unispiculous, rarely 

 more than bispiculous. Interstitial membranes sparingly 

 spiculous ; spicula same as those of the dermal membrane. 



"Colour, in the dried state, milk-white. 



^'Hah. On one of the Atlantic cables, 150 miles from the 

 Land's End {Sir James Anderson). 



" Examined in the dried state." 



EXPLANATION OF PLATE XIL 



Fig. 1. Acryptolaria exserta, Busk, with Scapus tuhidtfer, Norman, para- 

 sitic at a : natural size. 

 Fig. 2. A portion oi Acrr/ptoJaria exserta, magnified. 

 Fig. 3. A portion of the surface of Scapus tulruhfer, Norman, magnified. 

 Figs. 4-7. Hippothoa divaricata, var. caritiata, Norman, magnified. 



