1 78 Mr. W. T. Blanford on Hydrocena tersa and H. milium. 



The operculum is horny, extremely thin, and very difficult to 

 isolate ; it appears to be paucispiral. The animal, as represented 

 in Capt. Godwin-Austen's drawing, bears a most remarka- 

 ble resemblance to that of Assiminea, the eyes being above and 

 nearly at the tips of short blunt tentacles. The lingual teeth 

 are figured by Capt. Godwin-Austen as 5, ranged 2.1.2, 

 the outermost lateral teeth being probably rudimentary. 



The shell on the whole resembles Acicula more than any 

 other genus of opcrculated land-shells ; and as the characters 

 both of the animal and operculum approach those of that genus, 

 the present species may with probability be placed in it. The 

 teeth oi Acicula have not, so far as I am aware, been examined. 

 Those of Assiminea are very different from Capt. Godwin- 

 Austen's drawings. 



Acicula tersa is distinguished from all the typical species of 

 the genus by its shell being conico-ovate instead of subcylin- 

 drical, and, which is of much more importance, by the eyes 

 being pedunculated, and not sessile; for the position of the 

 eyes nearly at the tip of the tentacles shows that they are 

 situated on pedicels Avhich are connate with the tentacles. 

 The differences are not generic ; but I think they are sub- 

 generic, and I would therefore propose to make the present 

 species the type of a subgeneric section, with the name of 

 Acmella. It is just possible that Gi/clostoma striata, Quoy 

 and Gaimard, referred by Gray and Pfeiffer to Acicula, may 

 belong to the same subgenus. 



The following characters require to be added to those given 

 by Mr. Benson : — 



Testa cornea ; operculum corjicum, tenuissimum, paucispirale, nueleo 

 sinistrali. 



As regards Cyclostoma milium, I fear that I can add nothing 

 very certain. Amongst the very numerous small forms of 

 MoUusca collected by Capt. Godwin-Austen I have seen no 

 shell which I can witli certainty refer to Mr. Benson's descrip- 

 tion. I at first thought that a small aberrant Cyatliopoma, 

 collected near Cherra Poonjee, might be the species ; but it is 

 ribbed spirally, while Mr. Benson's species is described as 

 smooth ; and the proportions differ to too great a degree from 

 those of C. milium to allow of its being the same. All that 

 can certainly be asserted is that C milium must, on account 

 of its form and characters, be removed from the genera Hydro- 

 cena and Georissa, and that it may be a Cyctthoponia. It may 

 be an immature shell ; but if so, I am imable to suggest to 

 what species it can belong. 



The accompanying figures, with the exception of the oper- 



