Basnet Hall: Two New Isch iwckltoni-i. 121 



Dimrni^iniis.- Length, 6 iniu. ; breadth, 4 mm. 

 Sfofiou. 6 to 8 fathoms (dredcrod). 



Hdhitdt. — Ik'twfi'ii Phillip and Fr(Mith Ishiiuls. ^Vestern Port, Vic- 

 toria. 



2. Ischnochiton falcatus, n. sp. (PI. VITP, Fi<,'s. 2, a, b, c, d). 



IsrJittocJdfon tatemiKS, Tate, and May, non Bednall, Census 

 Marine Moll. Tasmania, Proc. fjinn. 8oc'. N.S.W., 1901, p. 413. 



Shell elevated ; moderately earinated. Colour ochraceouis, irre<j;u- 

 larly maculated with white, chietiy on the sides and anterior valve. 

 In some specimens nearly the whole jugal tract is white. Anterior 

 valve finely radially ribbed, the posterior margin strongly pustulose, 

 the projecting pustules imparting a serrated appearance^to the edges. 

 Median valves, lateral areas strongly raised, with two or three radi- 

 ating ribs, sometimes bifurcating towards the margin ; the posterior 

 rib strongly pustulose, the edge deeply serrated. Central areas deeply 

 sulcate, the sulci curving outwardly, the curves being most marked 

 near the jugum. Jugal tract with V-shaped striae, the apex directed 

 backwards. Posterior valve, mucro median ; the posterior half finely 

 radially ribbed like the anterior valve, the anterior half similar to the 

 central areas, the two sections divided by a pustulose rib. Girdle 

 with very irregular, striate scales. Interior bluish, with pink spot in 

 sinus and centre of end valves. Anterior valve having 11, median 1-1, 

 and posterior 13 slits. 



Dimensions. — Length, 15 mm. ; breadth, 9 mm. 



Station. — 6 to 8 fathoms (dredged). 



Habitat. — Between Phillip and French Islands, Western Port, Vic- 

 toria. (Frederick Henry Bay, Tasmania, Tate and May.) 



Re?}tarks. — This shell differs from I. tateanns in the much finer sculp- 

 ture of the anterior valve, the deep sulci of the central areas, and the 

 much coarser sculpture of the lateral areas. A specimen sent to me 

 by Mr. W. L. May, dredged in 10 fathoms at Frederick Henry Bay, 

 Tasmania, is identical with the Victorian shell now described. 



