GASTROPODA. 789 



2. Delos Jeffreysiana, Pfeiffer, 1853. Plate 31, fig. 2. 



Helix Jeffreysiana, Pfr., M.H. Viv., iii, 1853, 105; P.Z.S., 1852 (1854), 148; 

 Reeve, Conch. Icon., vii, pi. 130. f. 788 ; Hector, Cat. Land Moll. N.Z., 13. 

 Paryphanta Jeffreysiana, Pfr. : Hutton, M.N.Z.M., 24. Elcea Jeffreysi- 

 ana, Pfr : Hutton, T.N.Z.I., xvi, 208 ; Man. Conch. (2), i, 129, pi. 26. 

 f. 20. Rhenea Jeffreysiana, Pfr. : Heclley and Suter, P.L.S. X.S.W. 

 (2), vii, G31 ; Suter, J. de Conch., xli, 



Shell small, subdiscoidal, broadly umbilicated, thin, distinctly 

 striated, luteous, pellucid, shining. Sculpture of the protoconch con- 

 sisting of microscopic fine spiral stria-, which are continued over the 

 following whorls, being sometimes very distinct on the base, and in 

 addition there are radial and very irregular broadly rounded plaits. 

 which, however, occasionally are almost equidistant and rib-like. 

 Colour either uniformly luteous or with lively coloured chestnut streaks. 

 disposed in bundles ; specimens from Cape Maria are marbled with 

 chestnut and homy. Epidermis thin, translucent, shining. Spire 

 flatly convex, very little raised. Protoconch of If whorls, very little 

 rounded. Whorks 4, rather convex, gradually increasing, the last 

 depressed, not descending ; periphery and base rounded. Suture 

 impressed. Aperture slightly oblique, Innately oval. Peristome thin. 

 straight and simple, margins nearly uniting. Columella oblique. 

 slightly arcuate. Umbilicus broad, perspective, about one-third of the 

 minor diameter. 



Diameter Maj., 7 mm. ; min., 5-75 mm. : height, 3 mm. 



Dentition (Hutton, T.N.Z.I., xvi, 172, pi. 11, f. F). Formula of 

 radula 9 + + 9 ; transverse rows of teeth forming an obtuse angle. 

 Teeth robust, aculeate, smooth, the points rounded ; increasing in 

 size from the first to the fifth and then decreasing ; they are stouter 

 than those of D. coresia. 



Type, in the British Museum. 



Hab. North Island: Cape Maria van Diemen ; Whangarei 

 (A. Suter) ; Little Barrier Island (Adams) ; vicinity of Auckland : 

 Tuakau ; Tarukenga ; Mount Pirongia ; bush near Waitomo Caves 

 (A. Hamilton). 



Tribe 3. ELASMOGNATHA. 



The jaw with a well-developed dorsal appendage. 



Farn. ATHORACOPHORID^I, P. Fischer. 

 Jandlidce, Gray. 



Animal limaciform, with internal rudimentary shell, usually com- 

 posed of several pieces ; the mantle very small, sometimes triangular ; 

 no anterior tentacles ; pulmonary chamber with tracheae. Jaw elas- 

 mognathic. Radula with a small elongated central tooth, lateral and 

 marginal teeth very numerous, their reflection with several denticles. 



The family includes three or four genera : 



(1.) Atho-rocnphorus, Gould, New Zealand. 



