1906.] MOLLUSKS FROM THE PERSIAN GULF. 811 



Fam. Spondylid^. 

 Spondylus exilis Sowb. 



Spo7idpliis exilis G. B. Sowerbj, Proc. Malac. Soc. Lond. vol. i. 

 p. 280, pi. xviii. fig. 14 (1895). 



P.G. Foand adhering to the telegvaph-cable, 50 fathoms, 

 nmd bottom. 



I. Karachi, on voeks. Identical specifically with, but differing 

 in depth of coloration from Persian Gulf examples. 



Allied to S. gcedaropus L., the well-known Mediterranean 

 species. 



Spoxdylus gloriandus, sp. n. (Plate LIII. fig. 1.) 



S. testa oblique ovata, hmtd mtdttom crassa, aurantia vel albo- 

 carriea, apud umbones 2^'>-f'niceo-sic^usa ; umbonibtis acutiSy 

 p)rominulis ; costis temoissimis, numero circa 50, in'egidaribus^ 

 squamis jjarvis vel spinidis temiibtis, lo7igis, simpliciter jjrce- 

 ditis ; ai(,ricidis p)arvis. 

 Alt. Sj, lat. 3|, diam. 24 unc. {sp. maj.). 

 „ 2|, „ 2i, „ 1| „ {sp. min.). 

 Hah. Persian Gulf, off Dabai (1903) : on telegraph-cable that 

 had been left undisturbed for several years. Near Mussandam, 

 at 50 to 55 fathoms. 



A particulai'ly delicate and beautiful species, variously, though 

 not very highly, coloured, with orange, pale carneous, or white, 

 with dark pink suffusion at the umbones. The outer spines are 

 long, thin, simple, and tapering ; the many fine longitudinal ribs, 

 about fifty altogether, are ornamented with more abbreviated 

 spines or squamte ; these spines are most pronounced and con- 

 spicuous around the ventral margin or the posterior edge of the 

 left valve ; the auricles are small. One distinctive character is 

 its oblique form, showing greater exjDansion posteriorly, the 

 general shape being oval. 



.S'. exilis Sowb., also endemic in these seas, has its spines thicker 

 and far more foliaceous, the ribs fewer and coarser, than is the 

 ease v/ith S. gloriandvs. 



Spondylus xicobaricus Ohemn. 



I. Bombay (Abercrombie). Imperfect valves only. 



Spondylus rubicundus Reeve. 

 I. Bombay [Abercrombie). 



[Plicatula depressa Lam. 



I. Karachi [Major Baher). A species of the New World, and 

 here inserted with much doubt. It may be the next species, to- 

 which it is allied.] 



Plicatula pernula Melv. 



P.G. Malcolm Inlet. 24 fathoms, mud. 



