408 ]y[r. H. J. Carter on Deep-sea 



tered singly here and there. Internal structure compact, con- 

 sisting of cancellated sarcode confusedly charged with the 

 spicules of the species, together with minute foreign objects 

 like those of the dermal layer, traversed by the excretory 

 canal-system, which opens at the vents mentioned. Colour 

 of sarcode dark grey. Spicules of two kinds, viz. skeleton- 

 and flesh-spicules. Skeleton-spicules of three forms, like those 

 of P. amygdaloides^y'iz.: — 1, large triradiate, in which the 

 fourth arm or shaft is only represented by a short extension 

 of the central canal inside the spicule, or subquadriradiate, in 

 which this is extended into a short round prominence more or 

 less prolonged, arms of equal length, smooth, round, sharp- 

 pointed, somewhat curved, 50- by 6-1800ths inch (fig. 23, t, h) ; 

 2, similar to the foregoing, but much smaller, with the fourth 

 ray or shaft produced or not, and the three arms bifurcated or 

 not at the extremities (fig. 23, k k k) ; 3, linear, acerate, 

 fusiform, smooth, sharp-pointed, and slightly curved, much 

 smaller and more subordinate in this respect than the linear 

 spicule of P. amygdaloidesj 53- by -j-lSOOth inch (fig. 23, Z). 

 Flesh-spicule of one form only, viz. globostellate, with the 

 rays reduced to short round tubercles, mulberry- or blackberry- 

 like (fig. 23, 7?j,o,p), often presenting a distinct stellate in the 

 centre, whose rays respectively end in the short round tubercles 

 of the surface (fig. 23, m, n), 6-6000ths inch in diameter. 

 Although the average largest size of the spicules respectively 

 is easily obtained, there is a great variety in this as well as in 

 the forms of all, and they are all confusedly massed together, 

 mixed up with the flesh-spicules in great abundance as well 

 as with the minute foreign objects, especially consisting in this 

 instance of the siliceous balls of Geodia : perhaps the arms of 

 the large radiates lie flatter on the surface than anywhere else, 

 where they are partially hidden by the flesh-spicules among 

 which they are imbedded, and thus present a tessellated sur- 

 face ; but there is no cortex^ as before stated, and the dermal 

 surface is but the limit externally of the internal or general 

 structure and composition of the sponge. Size of specimen 

 about 1 inch high by 1 inch in diameter at the bottom. 



Hah. Marine, attached to hard objects. 



Log. Atlantic Ocean, in company with P. amygdaloides^ 

 near Cape St. Vincent. 



Ohs. There is but one specimen of this sponge ; and it is 

 contained in the jar with P. amygdaloides, under which the 

 number of the station &c. is mentioned. Although much like 

 P. amygdaloides as regards the presence of the large triradiate 

 and subquadriradiate skeleton-spicules, there is abundant evi- 

 dence in other respects for separation, as may be seen by the 

 descriptions of these two species oi PachastreUa respectively. 



