and Acapuico Sponges. 297 



mucli beyond a membranous form on most occasions. In tlie 

 first place, two species or one and a variety of it, occur, viz. 

 Hymedesmia Johnsoni^ which, in addition to the double- 

 liooked "trenchant" flesh-spicule, common to both (PL XI. 

 fig". 20, c, 6?, e), has a single form of aciiate skelelon-spicule, 

 viz. Esperian (PL XI. fig. 20) and a tricurvate flesh-spicule 

 strongly developed (fig. 20, h) ; the acuate spicule clearly, 

 from Dr. Bowerbank's illustration of a membranous growth 

 from Madeira (B. S. vol. i. p. 35, pi. xviii. fig. 293), indicates 

 that it is Hymedesmia Johnsoni^ Bk., and has been found 

 between the north of Scotland and the Faroe Islands, as above 

 stated, also on a Stclletta coming from Madeira in a mem- 

 branous form by myself ; to which we may add the coast of 

 Portugal probably (Schmidt, Spongf. Atlantisch. Gebiet. 

 p. 54) ; as well as that from Shetland figured by Dr. Bower- 

 bank in 1874 (B. S. vol. iii. p. 208, pi. Ixxiv. figs. 1-3) 

 under the name of Halicliondria falcula, which is probably 

 the largest massive specimen (being about 2 inches long and 

 1 inch broad) that has yet been obtained. Although the tri- 

 curvate spicule is only mentioned in the specimens from the 

 north of Scotland and Madeira, the acuate spicule is sufficient 

 for identification in the others. 



Schmidt's form, on the other hand, was obtained from the 

 coast of Florida, and from its possessing in addition to the 

 trenchant anchorate an acerate skeleton-spicule, accompanied 

 by a hihamate flesh-spicule only (PL XI. fig. 21, a, h), might 

 be termed Hymedesmia Schmidtii. His specimen was mera- 

 braniform (Spong. Atlant. Gebiet. p. 53) ; and this form and 

 spiculation also occur among the dredgings of H.M.S. ' Por- 

 cupine,' as evidenced by a small fragment of a massive speci- 

 men obtained at the entrance of the English Channel in 725 

 fms. at Station 36 ; so that there are evidently two different 

 spiculations of this sponge characterized by the same peculiar 

 anchorate, however much alike the general forms may be. 



At the conclusion of his article on Desmacidon Johnsoni^= 

 Hymedesmia, Bk., Schmidt states that the " trenchant " spi- 

 cule (Bowerbank's term, because the inner edge of it is thinned 

 oft" like a knife) with hook at each end is allied to a bihamate ; 

 but in Hymedesmia Schmidtii the other flesh-spicule which 

 is so abundantly present is a veriiahle C-shaped and sigmoid 

 hihamate^ whose contrast in form with the early development 

 of the great trenchant spicule when both are about the same 

 size is most evident (PL XL fig. 21, a, h, c). The reversed 

 position of the hooks, viz. one turning right and the other 

 left ("rechtsund links"), like the ends of a bihamate, seems to 

 have influenced him in this decision (figs. 20 & 21, c). But 



