XX ACHATINELLID.E. 



Family ACHATINELLID.E Tryon. 



Achatinellida TRYON, Structural and Systematic Conchology, 

 iii, 1884, p. 64, exclusive of Auriculella and Tornatellina. 



Orthurethrous land snails having an oblong, ovate or rarely 

 Helicoid shell, umbilicate or imperforate, generally with a 

 spiral columellar lamella in the last whorl, the outer lip simple 

 or thickened, not reflexed; no parietal lamella or tooth. 



Kidney not much longer than the pericardium, passing into 

 a long ureter reaching nearly to the collar. Venation of the 

 lung extremely minute, the pulmonary vein having no large 

 branches. Penis bears a long appendix; vas deferens free 

 throughout. Spermatheca imbedded in the albumen gland, 

 its duct long. Tentacular retractor muscles free from the 

 columellar muscle throughout. 



This family is confined to the Hawaiian Islands, with the 

 exception of the genus Fernandezia from Juan Fernandez, 

 now placed here provisionally. No other forms, living or 

 fossil, are known from other regions. It is rather remotely 

 related to the Partulidcz, more closely to the Ferussacidce; 

 and the minute Tornatellinidce are probably not distant. Two 

 very strongly differentiated subfamilies exist. 



ACHATINELLIN^E, arboreal forms, usually with light or 

 bright-colored shell, the sculpture of embryonic shell spiral 

 when present, jaw extremely thin, teeth of peculiar shape and 

 in v-shaped transverse rows (see vol. XXII). 



AMASTRIN^. Mainly terrestrial snails with less conspic- 

 uous coloration, the apical sculpture generally axial when 

 present, jaw stronger, teeth (see p. 129) resembling those of 

 Achatinidce, in nearly straight, transverse rows, 



Key to Genera of Amastrina. 



a. Oviparous ; shell ovate-conic or oblong-conic, glossy, rather 

 small (5 to 15 mm.), the apex obtuse, rounded. 

 &. Forms from Juan Fernandez. 



Genus FERNANDEZIA, p. 93. 



6 1 . Hawaiian forms. Genus LEPTACHATINA, p. 1. 



a 1 . Viviparous. 



Z>. Shell Heliciform, much wider than high, umbilicate. 

 c. Embryonic whorls projecting, convex, last 



