and Acajmlco 8i)07ifjes, 291 



Spongf. Adrit, Meeres, Taf. v. fig. 2 ; and my own of Esperia 

 v^V/osa, ' Annals,' 1874, vol. xiv. pi. xiii. fig. 13, r/) ; after 

 Avliich the soft structure maj again spread partially or wholly 

 over it, so that the specimens often present themselves with 

 much of the skeletal fibre still, so to speak, unclothed. This, 

 however, is only where the fibre-skeleton is very rigid, which 

 is not the case in all instances, as in Esperia {Rhaphiodesma) 

 linqua, and also in the West-Indian species about to be de- 

 scribed, in which thediflerence in the structure is not so much 

 marked. Indeed the type specimen of the former, viz. 

 IiJiaj)hiodesm.a lingua^ Bk., seems to have been squeezed up 

 together into its present " tongue-shape " by the haud, which 

 does not seem improbable, seeing that the type specimen 

 which Mr. Peach sent to Dr. Bowerbank froiv Shetland " was 

 cut to pieces in the dredge and rotted in drying " (Brit. Spong. 

 vol. ii. p. 190). Sometimes the lacework of the dermal layer 

 oi Halichondria iKinicea is so much like that of Esperia that, 

 Vi'ithout microscopic examination of the spicules, the difi^"erence 

 cannot be determined. AVe shall also find by-and-by that 

 there is a still gi'eatcr resemblance in this respect between 

 Esperia and Hi/iuedesmia Johnsoni of the following group. 

 In the meanwhile I will describe the AVest-Indian specimen. 



Esperia loivis^ n. sp. 



Massive, sessile, lobate. Consistence light, soft. Texture 

 toraentose. Colour light brown, in some parts reddish. Sur- 

 face irregularly lobate, uniformly covered by the dermal layer 

 above mentioned, but with the stelliform arrangement of the 

 spiculation for the most part reduced to an amorphous con- 

 dition. Agents on the sunnnits of the lobes. Internal struc- 

 ture more fibrous, but with the spiculation almost as much 

 confused as in the dermal one. Spicules of five forms, viz. : — 

 1, skeletal, for the most part acuate, slightly curved, smooth, 

 shaft fusiform, broader in the centre than the obtuse end, 

 abruptly sharp-pointed, about 115 by 3-6000ths inch in its 

 greatest dimensions (Fl.XI. fig. 16, a) ; 2, flesh-spicule, inequi- 

 anchorate, about 18-6000tlis inch long, head and naked part 

 of shaft about equal in length, smaller and about one third of 

 the whole, arms at their ends respectively equal in length 

 (fig. 16, h) ; 3, flesh-spicule, bihamate, smooth, C-shaped, 

 more or less sigmoid, about lO-6000ths inch long (fig. 16, c) ; 

 4, flesh-spicule, trichites, separate, and in sheaf-like bundles, 

 about 16-6U00ths long (tig. 16, </) ; 5, ?»??h<Y(; inequianchorate, 

 in which the arms of the head nearly extend down to the 

 lower or smaller end, and the latter presents an elongation of 

 the shaft (?) into a pointed process about 5-6000ths long (fig. 16, 



