197 



Dim. — Antero-posterior diameter, 3'2 mm.; umbo-ventral, 

 4'o ; sectional of closed valves, 3'6 mm. 



Locality.— O^ Beachport, 49, 100, 110, 150, 200 fathoms; 

 off Cape Jaffa, 90 and 130 fathoms; off Cape Borda, 55 fa- 

 thoms: east of Neptunes, 45 fathoms. Only one living speci- 

 men was taken in 45 fathoms. Valves were secured in num- 

 bers, chiefly between 45 and 110 fathoms: beyond this depth 

 they were few. Mr. Hedley reports to me that it has been 

 taken in 80 fathoms, 22 miles east of Narrabeen, New South 

 Wales. 



Diagnosis. — It somewhat resembles Crenella globularis, 

 Tate, a tertiary fossil : but this is a wider shell comparatively, 

 and more symmetrical. 



The generic location of this shell has been somewhat diffi- 

 cult, and Mr. Hedley and Mr. Etheridge and Mr. Kesteven 

 have compared it with allies in the Australian Museum, Syd- 

 ney, and discussed its characters, and as a result it has 

 been placed in Ar cope ma, and becomes a second recent Aus- 

 tralian species of this previously fossil genus, the first, A. 

 recens, having been figured and described bv Tate in Journ. 

 Mai. See, Lond., 1897, p. 181. 



Leptothyra carinata, n. sp. 



Figured in Trans. Roy. See. of S. Austr.. vol. xxxi., 1907; 

 pi. xxix., fig. 8. 



Shell minute, solid, three and a half whorls. The first 

 two whorls are smooth, white and convex. The spire-whorl 

 shows three rounded carinations, one just below the suture 

 which is channelled by it, the second about one-third the 

 distance between the sutures, and the third about one-fourth 

 the distance from the lower suture. The' interspaces are con- 

 cave, and have spiral cords, equidistant; two in the upper 

 space, the posterior the smaller; three in the middle space, 

 small and equal. The body- whorl has seven carinations 

 which become gradually lower towards the base, and closer; 

 interspaces concave, and provided with spiral lirae, varying 

 from six to two, according to the width of the spaces. The 

 lowest carina forms a margin to the umbilicus which is wide 

 and sculptured with about eight spiral lirse. The spirals are 

 cut up at irregular intervals by radial incisions, and marked 

 by very fine crowded microscopic radial scratches. The aper- 

 ture is circular; its inner surface smooth, and its outer scal- 

 loped by the spirals. Colour, very light amber; some ex- 

 amples are white, others faintly tinged with pink 



Dim. — Largest diameter 1"4 mm., smallest 1 mm.; height 

 I'l mm.; width of aperture, 7 mm. 



