298 Mr. IT. J. Carter on some West-Indian 



setting asiJe for a moment the fact tliat in Ilymedesinia 

 Schmidtii the trenchant spicule is accompanied bj genuine 

 simple C-shaped bihamates, we find in the other sponge which 

 I have placed in this group, viz. Desmacidon tittibans, Sdt., 

 that the central arm at both ends of the undoubted anchorate 

 is similarly reversed and accompanied by an abundance of 

 C-shaped bihamates, although of unusual size (PI. XII. iig. 24, 

 c-h). Comparing this anchorate, then, to the trenchant spicule 

 of H. Schmidtii as well as to that of H. Jolinsoni^ which is 

 the same, we must infer, I think, that this spicule represents an 

 anchorate as I have called it, and not a fibula or bihamate. 



Lastly, it has been generally supposed that no equiancho- 

 rates are ever found in the " rosette"-form presented by the 

 ^'/^equianchorates in Es-peria\ but in Schmidt's type specimen 

 oi Desmacidon titid)ans, in a slide at the British Museum, 

 may be seen " rosettes " of the equi Rxichoraie peculiar to this 

 species and similar to those oi Esperia (PI. XII. tig. 24, h). 



1-Jetuvning now to tlie grou]:> Esperina, I have observed that 

 in some species of Esperia there is a very minute equinYiclio- 

 rate of the navicular shape in great abundance and not more 

 than 2^-0()OUths inch long (PI. XI. tig. 19, a, h\. This was 

 lirst noticed in specimens belonging to the British Museum, 

 viz. in nos. 12;> and 286, both of which, unfortunately, are 

 without locality, while the other figures on them are " 28 a " 

 and " 68. 11. 26. 24 " respectively ; and just now I have found 

 it in the mounting of a specimen from this beach (Budleigh 

 Salterton) otherwise possessing a spiculation like Esperia 

 forea^ Bk., but with the skeleton-spicule a simple acuate, i. e. 

 without any inflation of the blunt end. It is also present in 

 a sj)ecimen from the Mauritius (j&\^?/i^?ho.w, mihi), to be here- 

 after mentioned. Schmidt also noticed this kind of minute 

 equianchorate as a " variety," in the spiculation of his 

 Esjyeria anceps, figured in his report of the sponges found by 

 the ' Germania ' in her expedition of 1871 to the North Sea 

 (Taf. i. fig. 8), of which the nieasurement is given under its 

 other name, viz. Desmacidon anceps (p. 432) as '' 0*03 mil- 

 liui.," which is much the same as that above stated, hence 

 very minute. It certainly is more minute than the minutest 

 inequiauchorates visible in the same slides; and therefore the 

 '/^^equianchorate may possibly heqin its development in this 

 form. Ilowever, it does not a])pear in the ovular embryo of 

 Esperia, while the ?'??equianchorates do, as my representation 

 will show ('Annals,' 1874, vol. xiv. pi. xxi. fig. 25). The 

 specimen of Esjjcria from the Mauritius in which this minute 

 equianchorate occurs was j)icked up by Col. Pike some years 



