TRIBE NYMPHACEA. 59 



smooth and rather small, orange yellow, pellucid, gaping at the 

 margin : hinge callous, palleal scar simple. J-. — Mauritius. 12 



P. Violacea. Desk, in E. vol. 3. p. 852. — Solen V. Lam. 

 20.— Deles, t. 2.f. 5. Oblong, with the extremities rounded, an- 

 teriorly narrower, both within and without violet with paler rays ; 

 nymphaj prominent : hinge with an obsolete tooth in one valve, in 

 the other a perfect and imperfect one. 3. — Indian Ocean, 



P. Costata. Nobis, in Z. P. 1842. Sub-elliptical, anteriorly 

 rather longer and angulated ; posteriorly narrowed and rounded at 

 the extremity : dull, whitish, with livid rosy narrow rays, and most 

 irregular crowded coarse transverse ribs, which often so unite on 

 the anterior slope that one is formed from two : inside glossy pur- 

 plish or yellowish, the rays distinct, the nymphse purple. 1 .. 1|. — 

 Australia. — Had not M. Deshayes assured its that the Virgata 

 of Lamarck was merely a Ferroensis, we should have considered this 

 sliell to have been that species. 



P. Costulata.* Turt. Biv. t. 6.f. 8.— P. Discors Phil p. 23. 

 t. 3. f. 8. Oblong, posteriorly rounded and rather longer, an- 

 teriorly obtusely angulated, very thin, anterior slope only with radi- 

 ating grooves, elsewhere nearly smooth, white with interrupted 

 sub-radiating scarlet marks, and a short scarlet radiating streak 

 proceeding posteriorly a little distance from the beaks. ■J-..1. — 

 Sicily, §'c. 



P. Lineolata. Gray in Yates New Zeal. Oblong, transverse, 

 compressed, obliquely truncated, anteriorly purplish rosy, with 

 rather darker concentric belts of very thin anastomosing radiating 

 lines, f . . 1 . — New Zealand. 



P. Variegata.— Solen V. Wood. G. C. t. 34./. 2. 3, 4.—D. 

 p. 68. — W. t. 3. f. 32. Ovate-oblong, anteriorly rather longer, 

 sub-truncated, gaping ; thin, pellucid, rosy orange, with purple 

 rays, which are stronger anteriorly, nearly smooth: hinge with two 

 teeth in one valve, one in the other. | . . 1 . 



P. Castrensis.— Solen. C. Chem.f. 1935, 6.—D. p. 6Q.— W. 

 t. 3.y. 25. Oval, rather longer and more obtuse anteriorly, very 



2 This species belongs to the genus Galeomna, Turton, whose 

 characters are as follows : — 



GALEOMNA. 



Transverse, equilateral, equivalve, ventral margin widely gaping : 

 gape oval-oblong ; hinge toothless, callous, with a small pit for 

 a sub-internal ligament under the beaks ; two very small and 

 very distant muscular impressions : palleal scar simple. 

 G. Turtoni.* Zool. Jour, vol 2. t. 13. /. 1.— Sow. G. f. I. 



2, 3. — Reeve, t. 54. f. 1, 2, 3. Ovate-oblong, transverse, white, 



with very fine longitudinal waved striae ; hinge thickened, palleal 



scar simple and wrinkled. 



