264 RECORDS OF THE AUSTRALIAN MUSEUM. 



ISCIINOCHITON MAYI, Pihbry. 



(Plate lxxiv., tig. 28.) 



Ischnochiton (Haploplax) mayi, Pilsbry, Nautilus, 1895, viii. , 

 No. 11, p. 128. 



Since this species has never been illustrated, we figui*e an 

 example from Frederick Henry Bay, Tasmania, received from 

 Mr. W. L. May. The description is iu a serial known to few- 

 local workers, and we therefore reprint the following original 

 description : — 



Shell, short-oval, moderately elevated, carinated, the side slopes 

 slightly convex. Surface smooth to the naked eye, but finely 

 granular. Color of valves and girdle uniform black above, or 

 slightly brownish at the beaks when eroded. 



The intermediate valves have almost straight sutures, even a 

 trifle concave in old specimens, the beaks projecting a trifle in 

 young ones. Lateral areas distinctly raised (the diagonal distinct 

 and rather wide), sculptured with several arcuate indistinct 

 growth marks, sometimes showing very slight traces of coarse, 

 low pustules, but these are hardly mentionable ; all over minutely 

 granulose in diamond pattern. Central areas with faint growth- 

 strice anteriorly, distinctly granulose at the sides, the granules 

 arranged to form forward converging riblets, which, though 

 slight, are apparent on the outer half of each valve ; central 

 portion of central areas smoothish, with faint granulation only, 

 beaks smooth. End valves sculptured like lateral areas. Valve 

 viii. with mucro projecting, at about the anterior third ; the 

 posterior slope concave below the mucro and then straight. 



Interior dull blue-green, greener behind the rather heavy 

 valve-callus, the depth of the cavity rather lead colour. Sutural 

 lamina? small, projecting less than half the length of a valve, 

 sinus wide. Slits in valve i., 1 1, valves ii. to vii., 1-1 ; valve viii., 

 12-13. Teeth sharp, smooth and short. 



Girdle black, clothed with densely imbricating, coarse, convex, 

 smooth scales. 



Length 8, breadth 6 mm. ; large " curled " examples would 

 measure at least 10 mm. long. Divergence the same as in 

 /. smaraydinus. 



