EEPORT ON THE LAMELLIBRANCHIATA. 139 



ochreaceous or brownish-ochre colour, leaving triangular white spots among them. 

 Sometimes the lower portion of the valves have angular zig-zag lines, displaying a 

 somewhat irregular transverse arrangement. 



This species was not recognised by Romer at the time he wrote his monograph, but 

 I am inclined to think he may have described it under another name. His Cytherea 

 soUgena must be very closely allied to, if not identical with, this species. Although no 

 mention is made of a brown stain within the valves at the umbones, in the copy of 

 his monograph before me, figure 16 exhibits, in front "of the beaks, a purplish blotch as 

 seen in Cytherea hebrcea, which is indicative of the mark within. Romer's shell is 

 very like the specimen figured by Reeve, Ijut a little higher, and has the same character 

 of markings as the single valve" obtained by the Challenger Expedition. Cytherea 

 pellucida, Lamarck, approaches very closely to this species, but may be distinguished 

 by the absence of the internal brown blotch, the presence of a dark stain on the lunule, 

 the brown wavy lines upon it at times crossing the incised line which suiTounds it, and 

 a more deeply sinuated pallial line, the sinus extending almost if not quite to the centre 

 of the valves. The style of markings and colour is very similar, and the hinge, about 

 the same in composition, is not quite so stout as in Cytherea hebrcea. Care must also 

 be taken not to confound Cytherea hehrcua with Cytherea varians of Hanley, a species 

 found on the coast of Brazil. This shell is more acuminate in front, more strongly 

 striated, has a brown spot upon the otherwise white lunule immediately under the 

 umbones, a stouter hinge, a different style of painting, and no stain in the interior at 

 the beaks. 



Cytherea (Caryatis) coxeni, Smith (PI. I. figs. 7-7e). 



Cytherea {Caryatis) coxeni, Smith, Eeport of the "Alert" Mollusea, p. 95, pi. vii. fi^;s. A-A-. 



Testa parva, inajquilateralis, trigono-ovata, utriuque subacuminata, mediocriter con- 

 vexa, alba, lineis teuuibus paucis punctisque pallide rufis ornata, striis sulcisque concen- 

 tricis angustissimis exarata. Margo dorsi utriuque valde declivis, postice arcuatus, antice 

 subrectus, brevior ; margo ventralis late curvatus, ad latus anterius oblique uscendens. 

 Umbones parvi, modice acuti, albi, aut dUute rufescentes, incurvati. Lunula elongato- 

 cordata, incrementi lineis striata, vex depressa, in medio paulo elevata, linea impressa 

 succincta. Ai-ea nulla. Cardo fortis, dente mediano valvas sinistrse crasso, laterali 

 magno, elevato, parum compresso. Cicatrix antica ovato-pyriforniis, postica rotuudior, 

 major. Sinus pallii subquatratus, superne oblique truncatus. 



This species is longer than high, ovate-subtrigonal, ver}^ inequilateral, moderately 

 convex, white, marked at intervals with narrow aubpellucid zones, and ornamented with 

 very fine, somewhat angular lines and dots of a light red or brown colour. This 



