129 



CATALOGUE 



OP 



TRUNCATELLIDiE. 



" Shell spiral ; whorls gradually enlarging. Apex acute, deci- 

 duous. Aperture ovate. Peristome continuous. Muzzle broadly 

 two-lobed. Jaws distinct. Tongue linear. Teeth ? Ten- 

 tacles compressed, short, diverging. Eyes large, black, with a 

 peculiar, very visible, prominent white pupil on the inner hinder 

 part of the base of the tentacles. Foot very short, rounded. 

 Operculigerous lobe simple. Operculum horny, ovate, of few 

 whorls. Walks with its foot, its dilated lips forming an in- 

 termediate loop." — Gray's Guide, $c. p. 94. 



" A pair of jaws and single branchial plume."— Clark, Brit. 

 Mar. Test. 383. 



Teeth of T. Montagui 3 • 1 • 3. The central rather narrow, 

 with a recurved central lobe ; inner lateral broad ; inner upper 

 edge with three broad denticles ; central father like inner, but 

 narrower and more oblique ; outer conical, compressed, curved ; 

 apex denticulated. 



1. TRUNCATELLA. 



Shell imperforate, turrited, always truncate when adult, 

 rather cylindrical, smooth or ribbed. Aperture oval or ellip- 

 tical. Peristome rather continuous, straight or slightly ex- 

 panded, simple or duplicate. Operculum thin, horny, impercep- 

 tibly sub-spiral, with a basal nucleus. 



Animal terrestrial, generally living on moist spots near 1 lie 

 sea. Head snout-shaped, used for walking together with the 

 short foot. Tentacles two, short, cylindrical, obtuse, bearing the 

 eyes between the posterior and interior part of their bases. 



Truncatula, Leach, fatal, ined. Is is. 

 Risso, 1826, Ear. Merid. iv. p. 124. 

 Menke, 1830, Syn. ed. 2. p. 43. 

 Lowe, 1831, Zo'ol. Journ. v. p. 299. 



G 5 



