20 F. Stoliczka — Land-sheUs of Fenaouj Island. [No. 1, 



Genus. TROcnOMonpirA., Alhers. 



Heliceen, Edit. E. v. Martens, p. 60, and Preussiche Exped nach Ost Asien 

 vol. ii, Landsclmecken, 1867, p. 245 ; Nigritolla and Vitlena, ibidem. Bivella, Blanf. 



The type of this genus is Helix trochiformis, Fer., which is characteris- 

 ed by a moderately solid, sub-discoid or depressedly conical shell, the whorls 

 being flattened above, the last carinate at the periphery, the aperture rhom- 

 biform or narrowly semilunar with simple - sharp edges, but the columellar 

 lips occasionally internally somewhat thickened and slightly reflexed. 



I do not know whether the animal of this typical species had been 

 examined, but I have observed those of about a dozen different species, which 

 evidently belong to the same type, and I find that all of them possess a 

 very fine glandular slit at the upper end of the foot, the pedal row being 

 in all also distinct ; they have, therefore, to be referred to the ZoxiTiDiE, 

 as already noticed in my paper on the Moulmain shells in Jom-. A. S. B., 

 vol. xl, pt. II, 1871, p. 225. 



Judging from a somewhat more intimate examination of the animals of 

 a few species, the following characters have to be added to those derived from 

 the peculiar shape of the shell. 



Animal moderately slender, with the posterior part of the foot shorter 

 than the anterior, the former terminating above with a small glandular slit ; 

 pedal row distinct ; mantle with elongated narrow neck lobes, but with the 

 shell lobes entirely wanting, left neck lobe sometimes divided or insinuated 

 in the middle ; jaw smooth ; genital organs without amatorial gland, or any 

 other appendages ; seminal receptacle and seminal duct very long. 



The Trocliomori)li(jB live on the ground generally in decaying vegetable 

 matter, under or on old wood. Three species have been found on Penang. 



Albers, while noticing several typical species, such as T. planorhis, 

 Less., under his genus Discus, referred to Trochomorplia a most varied 

 mixture of shells : for instance ; anceps, Grould, serrula, Bens. etc. Avhich 

 belong to Botula ; Barraclcpoorensis, Pfr., is a Kaliella ; cacuminifera and 

 infula, Bens, are Sitalw (== Conulema, olim) ; Ii. capitium, Bens., does not 

 belong to the present family, but to the next, the true Helicidas, etc. 



E. V. Martens (1. cit. pp. 246 and 217) adopted two groups in the 

 genus Trocliomorpha ; the one, for which he proposes the name JS'igritella, 

 includes the obtusely conoid and more solid shells, sometimes with a some- 

 what obtuse periphery ; these are true Trochomorplice, of the type of H. 

 trochiformis, or of Trocli. Ternatana, Guillou ; the name Nigritella is, 

 therefore, entirely superfluous. The second group is classed by Martens 

 as Videna, Adams ; it includes the more planorboid and sharply keeled 

 species of the type of H. planorhis. Less. For this same group, (type 

 H. castra, Benson,) W. T. Blanford proposed the subgeneric name Sivella, 



