Dr. J. E. Gray on the genus Assiminia. 421 



puraiFaseiotaria, Columbella, &c., I should not be able to distinguish 

 one from the other without the examination of the teeth or the lin- 

 gual membrane, and that would only enable me to separate Triton, 

 Cassis and Fasciolaria from each other and from Murex, Purpura and 

 Columhella, and not the three latter genera from each other; and it is 

 the same with the animals of several other orders and families ; — 



ffHniB 



Fig. l,;»i'>un I' 



cf,,..- 



i) «ji 



'io Hub 





r/p,fl ,§/! 



r .h) 

 id xd h- 



in tBOgjJ 



" d "llya^m 

 1. Truncatella truncatula p.^[yr^ a en 

 «. With foot extended, in the^t^J^^^^ j , 



drawing up the shell," ^ ' \ 

 b. Side view. -'>'^" ^-^^ ^*^^' 



e. Seen beneath as crawling up a 

 glass, when the muzzle is ex- 

 serted. 



Fig. 2. 



\o ■ 



'\[\, 2. Assiminia Grayana. 

 a. Under side of animal and shell. 

 h. Side view. 



c. Front of foot, showing' how the 

 lower lamina of the foot pro- 

 jects beyond the upper. 



yet the animals of the two genera Assiminia and Truncatella (see 

 figs. 1 and 2) proposed to be united, are so unlike in general ap- 

 pearance, minute structure and habit, that it is extraordinary that 

 any person should have made the proposal. 



I think the best way to show the distinction of these two genera 

 will be to copy, in addition to the extract already given, the figures 

 (see figs. 1 and 2) and descriptions of the animals given in different 

 authors, commencing with Mr. Lowe, who has figured and described 

 the animal of Truncatella in the fifth volume of the * Zoological 

 Journal,' and Mr. Berkeley's description and figure of the animal of 

 Assiminia ; then the description of the animal of the Indian species 

 of the latter genus, both printed in the volume above referred to ; 

 and, lastly, some extracts of additional peculiarity of the genus 

 Truncatella, observed by Mr. Clark, and published in his work on 

 British Mollusca. -i-v^i^i n«iiJ-^A. 



« 1. Truncatella. R. T. Lowe, Zool. Journ. v. 299. 1. 19. f. 4. 



^^Tentacula (2 contractilia) cylindrico-conica, hrevia, ohtusa, basi 

 distincta, proboscide separata ; oculis sessilihus paullo supra basis 

 angulum externum positis. Caput proboscidiforme exsertvm. Os 

 ad extremitafem proboscidis cylindricce, inter tentacula exsertce, 

 disciformem., supra emarginatain (so. bilobam, ob buccas labiates in 

 prohoscidem. ipsam coadunatas vel commutatas). Pallium collare 

 siphone nullo; orificio ad dextrum corporis ut in Helice, Melam- 

 pode, Pedipede, 8(C. Pes rotundatus vel ovalis, brevis, minimus, 

 posticus. Operculum corneum simplex, i. e. non spirale, ovale, 

 aperturum testa omnino claudens. Testa turrita; adulta cylin- 



