ANATOMY OP ACHATINELLID^. 57 



SOFT ANATOMY OF THE ACHATINELLID.E. 



Externally the animal of Achatinellida does not differ no- 

 ticeably from that of Partulidcz or of Bulimulidce. The foot 

 is usually shorter than the shell, rather broad, without divi- 

 sion into longitudinal areas. In progression the sole shows 

 advancing muscular waves. The lips, tentacles and eye- 

 stalks offer no peculiarities. Dorsal and facial furrows are 

 undeveloped or very weak. Small right and left body-lobes 

 are developed on the mantle. The genital orifice is some dis- 

 tance behind the tentacle, but seems nearer that than to the 

 mantle, in alcoholic examples. It is decidedly further back 

 than in Helicidcz. 



Pallial Organs. They resemble those of Amastra and Ena. 

 The surface of the lung is usually intensely black pigmented. 

 It is macroscopically plain, without visible mesh of arteries 

 and veins, only the pulmonary vein being visible. The kid- 

 ney is very narrow and long, prolonged ureter-like forward 

 nearly to the collar, where it opens by a pore on the intestinal 

 side. A narrow fleshy ridge runs from the apex backward a 

 short distance on the intestinal side. PL 20, fig. 3, Partulina 

 dolei. 



The jaw, when present, is excessively thin and delicate. It 

 is composed of narrow, more or less overlapping, vertical ele- 

 ments, which seem completely united. They do not converge 

 towards the middle (pi. 14, fig, 3, A. lorata). In some other 

 species no jaw could be isolated. There seemed to be merely 

 cuticle like that of the lower margin of the oral aperture. 



The radula is short and broad. It bears V-shaped rows of 

 teeth. These teeth are very numerous (150 in a half -row, in 

 A. lorata nobilis), all the side teeth are alike, and of a pecu- 

 liar shape which may be called rastriform, or rake-like; the 

 basal-plate being narrow and long, widening anteriorly, where 

 it is recurved, the reflection being broad, bearing 5 to 7 den- 

 ticles or delicate, acute cusps, which are unequal, the lateral 

 cusps being largest. In some species there is a narrow ' ' cen- 

 tral " tooth having a narrow bicuspid or tricuspid reflection., 

 In others a central seems to be wanting, or if present is not 



