102 "TERRA NOVA" EXPEDITION. 



_'."). Mill-mini ni/<//ixf, n. sp. Tl. II, tigs. 18, 19. 



Shell oblong, inequilateral, longer in front than behind, white, rounded anteriorly, 

 narrowed, shortly rostrate, and obliquely truncate posteriorly; valves thin, finely 

 roncentrically striateil. the right a little less convex than the left; the front dorsal 

 margin longer than the posterior, a little curved, but not much descending; hinder 

 margin obliquely sloping 1 , somewhat concave ; in both valves there is a faint keel 

 extending from the umbo to the extreme point at the hinder end ; two cardinal teeth 

 in each valve ; in the right the anterior tooth is thicker than the posterior, which is 

 bifid ; in the left the anterior is bifid, and much stronger than the hinder one, which is 

 quite slender, and directed backwards ; interior of the valves glossy, faintly radiately 

 striated at the ventral margin ; anterior adductor-scar elongate, posterior roundly 

 pyriform ; pallial sinus extending three-fourths across the valves, rounded in front. 



Length, 10 '5 mm. ; alt., 9 ; diameter, 4. 



Station 42, off Rio de Janeiro : 40 fathoms. 



Mm-diiiii tiN*/iii!/tK, Hauley,* from the Philippine Islands, closely resembles the 

 present species as regards form ; it is, however, rather more obtuse in front, and the 

 valves are more tumid and more glossy. 



26. Seini'li 1 cordiformis, Chemnitz. 



Tellina vttr<Uf<iniiix, Chemn., Conch. Cab., vol. XI, figs. 1941-2 (1795). 

 Ami>h!ilemiui cordiformis : Reeve, Conch. Icon., vol. VIII, pi. V, fig. 30. 

 Semclf ciirdiform/s : Smith, Proc. Zool. Soc., 1890, pp. 301, 321. 



Station 42, off Rio de Janeiro : 40 fathoms. 

 One small valve only. 



Some remarks on the synonymy and distribution of this species are given by the 

 present writer in the place cited above. 



27. JA/'V/w (Mactrinula) janeiroensis, n. sp. PL II, fig. 20. 



Shell broadly subtrigonal, a little inequilateral, longer behind the um bones than 

 in front, white, subpellucid, thin, concentrically plicate upon the umboues, and finely 

 striated with the lines of growth upon the lower half of the valves ; a rather sharp keel 

 running from the tip of the umbones to the posterior end of the valves marks off the 

 hinder dorsal area ; there is also a smooth lunular area ; the concentric ridges or 

 plic86 do not extend into either the lunular or the posterior area ; in the latter, one or 

 more faint radiating keels or ridges are also usually observable ; dorsal margins 

 oblique, at first nearly rectilinear, then curving downwards at the ends ; anterior end 

 sharply rounded, posterior rather more acuminate, ventral margin very widely 

 arcuate : umbones smooth at the extreme tip, inclined towards the front, a little 



us Ccmi-li.. vol. I., p. 302, pi. LV1I1, fig. ( .i.">, us T<-Uin. 



