Mr. W. H. Benson on the genus Diplonimatina. 193 



the tube. It is possible that in the specimen referred to, tlie 

 flowers are only in a young state, and that when fully grown 

 they may assume a somewhat greater development, but I give the 

 description in accordance with the specimen as it exists*. 



XXII. — Characters 0/ Diplommatina, a nevj genus of Terrestrial 

 Mollusks belonging to the Family of Carychiadse, and of a second 

 species contained in it ; also of a new species of Carychium in- 

 habiting the Western Himalaya. By W. H. Benson, Esq. 



At page 81, vol. ii. of Pfeiffer^s excellent Monograph of the 

 Helicidce, there appears an erroneous reference to that family of 

 an anomalous shell, the animal of which must exclude it from 

 the position there assigned to it ; — I allude to the little Himalayan 

 species called by Capt. Hutton in MSS. Carychium costatum, 

 which Dr. Pfeiffer has described under the title of Bulimus folli- 

 culus. Capt. Hutton, referring to the situation of the eyes and 

 to their not being borne on the summits of the tentacula, asso- 

 ciated the form with Carychium. The shell alone, differing in 

 the shape of the aperture and destitute of plaits or teeth, would 

 certainly be anomalous in that genus ; but it formed the only 

 published type to which the species could be approximated. The 

 following is the recorded result of my own repeated observations 

 of the animals of both species. 



Tentacula two only, originating from the upper part of the 

 head, long and filiform ; eyes situated on the posterior part of 

 the tentacula at their base, composed of two lobes : one lobe 

 deeply seated in the tentaculum and larger than the other lobe, 

 which is a small black point coming to the surface on the outer 

 side of the larger lobe ; foot short. 



Had the animal been provided with an operculum t, it might 

 possibly have been referred to the family of Cyclostomatidse in 

 accordance with the position of the eyes, and the form of the 

 aperture of the shell. The differences observable in the latter, 

 as well as in its inhabitant, give countenance to a separation from 

 Carychium ; I therefore propose for the type the following name 

 derived from the peculiarity of the percipient points or eyes. 



Diplommatina, nobis. 



Char. Ge«. Testa vix rimiita, tenui, subovata; spira elongata; an- 

 fractibus convexis, costatis, ultimo subascendente ; apertura eden- 



* A representation of this plant with details will be shown in plate 48 of" 

 the ' Illustr. South Amer. Plants.' 



\ 1 believe 1 have the concurrence of the major part of the conchologisfs 

 of the present day in dissenting from Rang's opinion, "qu'il n'estpas possible 

 d'etablir des divisions fondees sur la presence ou I'absence d'opercule. ' — 

 Vide Rang's Manuel, p. 198, x^rt. Litiopa, 



Ann. ^ Mag. N. Hist. Ser. 2. Vol. iv. 13 



