7G6 Mr. II. J. Carter on Deqi-stm 



Azorica Pfeifercs^ Carter, IS7 S, ? = Leiodermatium Lynceus, 

 Schmidt, 1870. 



The type specimen of this sponge is in tlie British Museum ; 

 and its general form is that of an expanded vase whose walls, 

 rising from a thick short stem, soon spread out in an undu- 

 lating manner into a head 14 inches in diameter, which has 

 the appearance of a large " double flower," on account of the 

 sinuous infoliations of the wall, which are so abundant as to 

 fill up tlie wliole of the vasal cavitj, Avith the sides and bottom 

 of which they are of course continuous. It is 11 inches in 

 vertical diameter, and the wall seldom more than g- of an inch 

 thick, slightly thinning towards the margin, which is round 

 and irregularly Assured or curvilinear. The surface is even, 

 especially on the outer side of the wall, where the pores are situ- 

 ated in the form of puncta closely approximated, and only 

 interrupted on the inner side of the wall, where the vents 

 are situated, by the latter, which in the form of single 

 circular holes, each with an elevated margin, are irregu- 

 larly scattered over this surface at some distance from each 

 other. 



The structure internally consists of that filigreed kind of 

 spicule common, as before stated, to the Lithistina generally, 

 faced by a dermal layer of siliceous network in which the 

 branching, although larger in some respects than in others, is 

 so irregular that it is impossible to divide it into distinct heads 

 indicative of its being composed of so many distinct dermal 

 spicules like those of the other Lithistina ; neither are the sup- 

 ports or shafts of these supposed heads a bit more distinguish- 

 able on the inner side of the dermal layer, on account of their 

 irregularly branching there also ; so that this layer cannot be 

 designated an irregular network. But on the branches of 

 both outer and inner aspects there are short, thick, oval tubercles 

 of a peculiar form, inasmuch as the summit of each respectively 

 presents a short thick branch, which soon divides once or twice 

 into crooked attenuated extremities, while the ends of many of 

 the branches terminate in the same manner ; but the branched 

 oval tubercle appears to me the characteristic feature of the struc- 

 ture, as I do not observe it to be so marked in any other species, 

 although that of Farrea densa ('Annals,' 1873, vol. xii. pi. 17. 

 fig. 6) is something like it. Besides this, the sarcode is charged 

 with an abundance of long, delicate, fusiform acerate spicules, 

 the largest of which are about l-14th inch in length by l-3000th 

 in thickness ; but these are only found towards the margin of 

 the frond-like Avail, where, coming from opposite sides, they 

 meet, and drying in their sarcode together, there form a more 



