and on Plectopylis, Pollicaria, and Hybocystis. 99 



that feature, and still belonging to Corilla with reference to its 

 original typical characters. 



The description of Corilla, with the addition of the pylaic 

 plication, will only tend to confusion, and must necessitate the 

 formation of another group for Messrs. Adams's typical forms ; 

 while it is evident, from Mr. Gould's description, that he had then 

 no knowledge of the affinity of species not referable to the Pla- 

 norboid group; and it would also appear that he was unac- 

 quainted with the existence of internal series of pylse. In 

 short, Mr. Gould's description of Corilla is calculated to include 

 all Messrs. Adams's species, adding a feature characteristic of a 

 portion only, and, thus altered, is still hampered with the acci- 

 dental Planorboid character. Such a subgenus would comprise 

 species not truly Plectopylaic ; and others which are really so, 

 but not Planorboid in form, would be inadmissible. 



In the same paper is described a large and interesting species 

 of the restricted genus Alycceus — A. Pilula, Gould, from Hong 

 Kong. Another species has lately been described from Java — 

 A. Jagori, Von Martens. The characters given of these two 

 species will not permit their assignment with certainty to any 

 particular one of the three sections proposed in the f Annals ' 

 for March 1859. A third species, A. exul, Bl., assignable to 

 the section Charax, was found during the past year in the Nil- 

 gherry range, by Mr. W. T. Blanford, as well as a singular 

 new Diplommatina. Neither of these two genera had previously 

 occurred to the south war/1 of the Ganges. In the same rich 

 locality, Mr. H. F. Blanford had, in a former year, discovered a 

 most curious little Cyclostomaceous genus (Opisthostoma, Bl.), a 

 specimen of which he has kindly communicated to me. These 

 new Nilgherry shells were destined to appear in the 'Journal of 

 the Asiatic Society of Calcutta '. 



I may here note that I have lately ascertained that the shell 

 which I published in the ' Annals' for March 1856, under the 

 name of Megalomastoma gravidum, was described in the f Pro- 

 ceedings of the Boston Society of Natural History ' for July in 

 the same year, as Cyclostoma Pollex, Gould. Mr. Gould pro- 

 ceeded, in the same paper, to propose for that shell, in conjunc- 

 tion with Rhaphaulus Chrysallis, Pfr., and M. (Hainesia) Myersii, 

 Haines, a new group, " probably generic," with the designation 

 of Pollicaria. This name, if published within a moderate period 

 after its submission to the Boston Society, has priority in point 

 of time to my generic term Hybocystis, proposed in the ( Annals ' 

 for August 1859 for H. gravida alone, after an examination of 

 the animal and operculum. The true structure of the shell of 

 Rhaphaulus Chrysallis (discovered by Mr. H. Adams) was made 

 known in the f Annals' for April 1856, in which year also 



7* 



