and AcajJtdco Sjionges. 293 



Schmidt's numerous species (and we need not go fui-ther back, 

 as it would only lead us into the region of doubt, which has 

 been well summed up by Schmidt himself, as before stated), 

 there are twelve species from the Adriatic, of which tea are in 

 his publication of 1862, and the two others, with figures of 

 the incquianchorate only of an " Indian species," in the 1st 

 Supplement ; three in the Atlantic sponges of 1870 ; three in 

 the report of the expedition to the North Sea (Deutschen 

 Meere) of 1871 ; two in that of the expedition of 1872 (Nord- 

 See Expedition) ; and one in that of the summer expedition 

 to the Baltic (Ost-vSee) in 1871 (Berlin, 187o, S. 148), viz. 

 EKperia Juclfera. Of these the figures of the anchorates of 

 the '^ Indian species " and two of the Atlantic ones, viz. E. 

 diaphaaa and E. iinmitis respectively, are the only ones which 

 seem to me to possess an amount of difference in their inequi- 

 anchorates respectively which renders them of any specific 

 value ; while all the rest are so much alike that the anchorate 

 alone is of no utility for this purpose. j\[y observations are 

 taken rather from Schmidt's type specimens on the slides in 

 the British Museum than from his published descriptions and 

 illustrations, in which I find that E. iinmitis is my E. socialis 

 of 1871, also from the West Indies (' Annals,' vol. vii, p. 276, 

 pi. xviii. fig. 7, &c.). 



Of the British species of Esperia represented by Dr. Bower- 

 bank, viz. Ilymeniacidon suhclavata (B, S. vol. iii. pi. xxxvii. 

 figs. 9-13) and lihaphiodesma jioreum (ibid. figs. 14-19), 

 both on valves of a Pecten^ the inequianchorates appear to be 

 alike, although the skeletal spicules are so far different in the 

 illustrations that the former is simply acuate, i. e. without 

 terminal inflation, and the latter sub-pinlike ; but this diffe- 

 rence, as I have said before, is not of much specific value, as 

 it is not more persistent tlian the absence or presence of the 

 tricurvate, which also, as before mentioned, exists in my 

 mounting of the latter. As for the anchorate of //. suhclavata 

 being " bidentate," this I regard as an ocular delusion, having 

 never found less than three teeth or arms if carefully looked 

 for, a fact which will be better understood by reference to my 

 descriptive and illustrated anatomy of the incquianchorate 

 ('Annals,' 1871, vol. vii. p. 277, pi. xvii. figs. 7, 8, &c.). 

 Thus, if the anchorate be viewed laterally, t"ily t\vo arms 

 will appear, viz. the anterior and the nearest lateral, giving a 

 bidentate aspect, while if it be viewed in front all three will 

 appear; but neither is so convincing as an end view, which 

 can only be obtained when the anchorate is tilted upwards ; 

 and then the two lateral arms, one on each side the shaft, with 

 the anterior arm in the middle supported on the "falcate" 

 septum, become convincingly obvious. 



Ann. & May. N. Hist. Ser. 5. Vol. Ix. 21 



