408 ^h. II. J. Carter on Deep-sea 



tcred singly here and tlierc. 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 Hesh-spicules. Skeleton-spicules of three forms, like those 

 of P. amij(jdaloides^\\z.: — 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, /, 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 h A:) ; 3, linear, acerate, 

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

 smaller and more subordinate in this respect than the linear 

 spicule of P. amygdahidesj 53- by -j-lSOOtli inch (fig. 23, Z). 

 P^lesh-spiculc of one form only, viz. globostellate, with the 

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

 like (fig. 23, ??i,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 Avith the flesh-spicules in great abundance as well 

 as with the minute foreign objects, especially consisting in this 

 instance of the siliceous balls of (reodia: 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 tlie 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. 



Hob. Marine, attached to hard objects. 



Loc. Atlantic Ocean, in company with P. amygdaloideSj 

 near Cape St. Vincent. 



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

 contained in the jar with P. aviygdahides, 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 tliese two species oi PachastreUa respectively. 



