TROCHOMORPHA. 



Genus TROCHOMORPHA Albers, 1850. 



Trochomorpha ALBERS, Die Heliceen, p. 116. MARTENS, Die 

 Hel. (edit. 2), p. 60, type trochiformis Fer.; Ostasiat. Zoo]., Land- 

 schn. p. 245. Discus ALBERS, /. c., p. 117. MARTENS I. c., p. 61- 

 type metcalfei Pfr. Not Discus Fitz., q. v. Nigritella MARTENS, 

 Die Hel. (edit. 2), p. 63, type nigritella Pfr. ; Ostas. Landschn., p. 

 246. Videna H. & A. ADAMS, Gen. Rec. Moll, ii, p. 115. MAR- 

 TENS, Ostas. Landschn., p. 247. Sivella BLANFORD, Ann. and Mag. 

 Nat. Hist. (3) xi, p. 86 (1863), type eastra Bens. Geotrochus v. 

 HASSELT, Algemeene Konst- en Letterbode voor het Jaar 1823, p. 

 233 (Trochomorpha sp. audSitala sp.) 



Shell varying from high trochiform to depressed lens-shaped, umbil- 

 icate or at least perforate ; solid and opaque, or thin and subtranslu- 

 cent ; carinated, at least in the young. Having 5-6 whorls. Sur- 

 face rather smooth. Embryonal whorl not marked off from the 

 after growth. Aperture basal, the upper lip terminating at the keel 

 or periphery ; peristome simple and sharp, or thickened and blunt, 

 the basal margin arcuate ; columellar margin arcuate, short, not 

 dilated or reflexed ; ends of lip distant. Type T. trochiformis Fer., 

 pi. 7, figs. 8, 9. (See also pi. 7, figs. 1-3, T. quadrasi Hid. ; pi. 7, 

 figs. 4-6, T. merzianoides Grt. ; pi. 7, fig. 7, T. meleagris Pfr.) 



Animal : Foot long and rather narrow ; sole flat, with no trace of 

 longitudinal division ; parapodial groove distinct, bounding a wide 

 vertically grooved foot margin, and having a shallower groove 

 above it. Tail depressed above, rounded behind, without a mucus 

 gland. Back with several indistinct longitudinal rows of granules; 

 sides irregularly granular. Shell lappets none; but mantle having 

 a wide body-lappet on the right and a small one on the left. Lung 

 orifice to the left of the superior angle of aperture, (pi. 8, fig. 12, T. 

 asvimilis Grt.; fig. 13, T. beckiana Pfr. ; pi. 9, figs. 32, 33, T. timor- 

 ensis Mts.). 



Genitalia simple, the penis moderately long, somewhat twisted, the 

 retractor muscle and vas deferens entering at the apex. Sperma- 

 theca on a short duct. (PI. 8, fig. 9, T. assimilis ; fig. 14, T. beck- 

 iana; fig. 17, T. troilus ; fig. 19, T. subtrochiformis ; figs. 15, 16, T. 

 metcalfei; pi. 7, figs. 14, 15, T. planorbis). Orifice of genitalia near 

 the pedal groove, below and slightly back of the right eye-peduncle. 

 Right eye peduncle retracted between branches of genitalia. Kidney 

 long and narrow. 



