and Acajnilco S^Jongcs. 295 



cupiiie ' between the north of Scothand and the Fiiroc Islands 

 will show (' Annals/ 1874 and 1876, vols. xiv. and xviii. 

 pj). 215 and 316 respectively). In Esperia cujjressiformis 

 (vol. xiv. pi. xiv. figs. 16-19) the general form and spicula- 

 tion will be found to be very remarkable ; while in the variety 

 hihamitifera (vol. xviii. pi. xiii. tig. 14) it is hardly less so. 

 The species E. horassus (ibid. fig. 13) has hardly any thing 

 to characterize it beyond the peculiar aiTangement of its 

 spicules, which have nothing remarkable in their forms beyond 

 the common run. In E. placoides^ however, we have all the 

 common characteristics in spiculation, together with the rigid 

 tibro-structure internally and the lace-like dermal layer in the 

 grooves or "pore-areas" (fig. 12, k^ I) between the placoid 

 plates, while the latter in their structure give the species 

 this striking peculiarity. But when we turn back to E. villosa 

 (vol. xiv. pi. xiii. figs. 13-15), there we find an e^'Wi'anchorate 

 instead of the usual Esperian form (that is, with unequal 

 ends), which makes one doubt the appropriateness of the 

 generic term, as will be more particularly shown by the fol- 

 lowing observations, viz. : — 



While engaged in looking over my slides of different 

 Esperice for the present occasion, I recurred to that bearing 

 the spiculation of the " Unknown Sponge," published in the 

 ' Journal of the Koyal Microscopical Society (1879, vol. ii. 

 pi. xviia, fig. 12), which, it may be remembered, was found 

 in the form of a mere film on the foraminiferal test of Aphro- 

 sina infunm'sj Carter, that, again, was on the branclied coral 

 Amplnkelia oculata^ Duncan, whicii had been dredged on board 

 H.M.S. ' Porcupine ' in the Atlantic Ocean, between the north 

 of Scotland and the Faroe Islands, and I immediately saw that 

 there existed a great resemblance — indeed, almost an identity, 

 between it and the spiculation of Espevia villosa. It may be 

 remembered also tliat, in both these instances, the bihamate 

 was strikingly large — that is, in the former 82|^-6U00ths and 

 in the latter 40-60U0ths inch long, a coincidence of large sizes 

 in these flesh-spicules which first attracted my attention to 

 the respective slides, as in no other case has the bihamate been 

 found so large. I have already stated that the anchorate was 

 ej'Ui'endcd in Esperia villosa ; and I might here add that it 

 is of that shape whicli I have termed navicular or weaver's 

 shuttle-like, thus totally op])Osed to the usual form in Esperia. 

 viz. i'nequianchorate, but precisely like that of the " Unknown 

 Sponge.^^ In the latter, being a mere film, there is nothing 

 but the spiculation to judge from ; but in Experia villosa 

 which is comparatively large, the surface is totally different 

 from that usually characteristic of E.peria^ as niay be seen. 



21* 



