280 GASTROPODA. [Pectinibranchin. 



simple ; gill-plume placed obliquely across the mantle-cavity, tlie 

 elongate linear laminae partly exposed. Central tooth of the radula 

 trapezoidal, the reflected margin triangular, having long sharp median 

 and very fine lateral cusps ; laterals multicuspidate ; marginals 

 simple. 



Shell conical, provided with epidermis, apex posterior and directed 

 to the right, more or less spirally curved ; aperture basal, the lip 

 continuous, no inner process, the horseshoe-shaped muscular impres- 

 sion on the inner wall. 



The few species inhabit the seas of Europe, the East and West 

 Indies, western America, Australasia, &c. 



Fossil. The genus commenced with the Silurian. 



]. Capulus calcareus, Suter, 1909. Plate 15, fig. 14. 



Capidus calcareus, Suter, " Records Canterbury Museum," i, No. 2, 1901), 

 122, pi. 12, f. 1, 2. 



Shell small, fairly solid, somewhat irregularly ovate, very little 

 asymmetrical. Sculpture consisting of fine radiate striae, crossed by 

 distinct concentric growth-hues ; most specimens I have seen had 

 partly lost the epidermis and the radiate sculpture, the surface being 

 quite smooth and chalky. Colour yellowish-brown ; white after 

 having lost the epidermis, which is thin, horny, and peeling off very 

 easily. Apex projecting far past the base. Protoconch well defined, 

 of 1J smooth and convex whorls. Whorls If, the last half large, 

 convex, expanded towards the aperture ; posterior slope below the 

 apex short, concave. Aperture oval to subcircular, expanded, margin 

 uneven, sharp ; inside white, polished. 



Breadth, 8-5 mm. ; length, 11-5 mm. ; height, 5mm. 



Dentition. Formula of radula 2+1+1+1 + 2. Central tooth 

 trapezoidal, with a large median and 4 smaller cusps on each side. 

 Lateral teeth with a large triangular reflection bearing 5 denticles 

 on the inner side. Marginals unciform, the inner teeth with sharply 

 pointed denticles on the posterior edge, outer marginals smooth. 



Type in the Canterbury Museum, Christchurch. 



Hob. Nine miles west of Cape Runaway, Bay of Plenty, in 105 

 fathoms, on dead shells of Megalatractus maximus, Tryon (type) ; 

 six miles east of Jones Head ; of! Lyttelton, in 100 fathoms (E. B. 

 Waite). 



Genus 2. NEOJANACUS, Suter, 1907. 



Neojanacus, Suter, T.N.Z.I., xxxix, 1906 (1907), 26(i. Type : N. perplexus, 

 Suter. 



Animal unknown. 



Shell having the appearance of the flat form of Crepidula contorta. 

 Q. & G., without a basal plate ; small, flattened, oval or oblong scuti- 

 form, with a minute subspiral apex and a horseshoe-shaped muscular 

 impression. 



Known from New Zealand only. 



