470 Mr. H. J. Carter on the 



uniformity of spines, from Aphrocallistes beatrix. Scale l-24th 

 to l-6000th of an inch. In general, it is a very ragged-looking 

 half- developed spicule. 

 Fig.W. Portion of the commencing vitrification of the skeleton in a 

 young Aphrocallistes Bocagei, not more than two twelfths of an 

 inch in diameter, showing the enclosure of the sexradiate with 

 spined feather-like arm among the other spicules ; also the cha- 

 racteristic rosette : a a, spicules with feather-like arm ; b b, other 

 spicules ; c c, vitrified sarcode spreading over the same ; d, form 

 of rosette. Scale l-24th to 1 -6000th of an inch. 



N.B. This appears to be Schmidt's Lanuginella pupa. It is 

 found growing on a branch of Lophohelia prolifera close to a 

 living Aphrocallistes Bocagei, just as Schmidt has represented it 

 growing in abundance on Aphrocallistes Bocagei itself (Atlantisch. 

 Spongienf. pi. ii. fig. 1). It cau only be confounded with the 

 structure of Sympagella mix, Sdt., whose characteristic ladder- 

 like vitreous fibre and the pappiform rosette, however, point out 

 the distinction. 



Plate XVI. 



Deciduous vitrified Jibre. 



Fig. 1. Aphrocallistes Bocagei. Fragment of dead specimen dredged up 

 from muddy bottom at the western entrance to the English 

 Channel, in 725 fathoms, by H.M.S. ' Porcupine,' showing that 

 the fibre is based on sexradiate spicules whose presence is 

 rendered evident, after the fibre has become deciduous, by a 

 process of absorption which, if not gone too far, leaves a perfect 

 mould of the imbedded spicule, a a, spiniferous vitreous fibre ; 

 b b, moulds of spicules ; c c, puncta indicating spines on the 

 surface of the fibre. 



This specimen, or the portions which were still filled with 

 mud having been boiled in liquor potassse, yielded an abundance 

 of the rosette and scopuline spicule peculiar to Aphrocallistes 

 Bocagei. 

 Fig. 2. Aphrocallistes Bocagei. Fragment of dead specimen dredged up 

 from muddy bottom on the north-west coast of Spain, on board 

 the yacht ' Noma ' (depth not mentioned), showing an enclosure 

 of the scopuline spicule in the vitreous skeleton (PL XV. fig. 1) : 

 a, spiniferous vitreous fibre or skeleton ; b, scopuline spicule. 



Although this specimen was treated with liquor potassse in 

 the way above mentioned, it yielded neither rosette nor scopuline 

 spicule. Thus, but for the presence of the latter involved in 

 the skeleton, there might have been (and indeed was) a doubt 

 as to the species. Figs. 1 and 2 are on the scale of l-12th to 

 l-1800th of an inch. The difference in size is owing to the dif- 

 ference in the size of the fibre in the two specimens figui"ed. 

 Fig. 3. Aphrocallistes Bocagei. Fragment involved in the Gummina 

 ( Corticium abyssi) enveloping Farrea occa, which had grown on 

 a dead Lophohelia prolifera dredged up from muddy bottom at 

 the western entrance of the English Channel, on board H.M.S. 

 ' Porcupine,' in 500 fathoms (see sketches of specimen, 'Annals,' 

 1873, vol. xii. pi. i. figs. 1 & 2), showing an enclosure of the 

 sexradiate spicule with feather-like arm in the vitreous skeleton 

 (PI. XV. fig. 9) : a a, spiniferous vitrified skeleton ; b, sex- 

 radiate spicule with feather-like arm. Scale l-12th to l-1800th 

 of an inch. 



