APPENDIX. 353 



t. 19, /. 19. Bluntly and rather obliquely subquadrate, extremely 

 inequilateral, thin, ventricose, white under a very thin olive skin, 

 smooth, subarcuated ventrally. Front extremity broadly rounded, 

 its dorsal edge scarcely sloping ; extremity of the excessively short 

 hinder side obtuse in the middle, towards which a faintly depressed 

 line runs from the small and incurved beaks. Umbones much 

 swollen : no marked umbonal ridge. Ligament elongated, not 

 sunken : inside bluish white. !§-. Senegal. In each valve is a 

 transverse laminar lunular tooth, and a very slender cardinal one; 

 a compound sublaminar tooth intervenes in the right valve. 



Cyeenoida Cumingii (t. 15, f. 5). Broadly suboval, subinequi- 

 lateral, thin, swollen, white under a slight dirty yellow epidermis, 

 smooth, with a faint umbonal ridge ; ventral edge arcuated, ascending 

 evenly at each extremity ; front extremity bluntly (not broadly) sub- 

 biangulated, its dorsal edge hardly sloping ; hinder extremity rounded, 

 its dorsal edge scarcely, if at all, incurved : umbones moderately pro- 

 minent ; beaks very small, incurved ; neither lunule nor lozenge ; 

 ligament short, narrow, not projecting: inside white: a deeply 

 cloven and a small simple cardinal tooth in each valve. ]%. 

 Philippines. 



Cyrenoida oblonga (t. 15, f. 6). Transverse, subquadrate-oboval, 

 inequilateral, thinnish, more or less ventricose (especially in front), 

 both within and without glossy white, partially covered with a slight 

 epidermis of a canary-yellow, smooth, arcuated at the ventral margin ; 

 front side rather the shorter, evenly rounded ; hinder side bluntly 

 angular above, rounded below, its dorsal edge almost horizontal ; um- 

 bones little prominent ; beaks inclined : no lunule ; ligament short, 

 small, narrow, seated in an elongated narrow shelving area, whose 

 sides are sharp at the edge ; teeth as in C. Cumingii. li. Philip- 

 pines. The surface is retuse between the area and the site of an 

 umbonal ridge. 



On Galathea (p. 93). Dunker has published a G. Bengoensis, 

 and Philippi G. Iceta, rubicunda and tenuicida in the Zeit. Mai. 1848, 

 1849. 



On Cyprina (p. 95). C. triangularis and minima (p. 95) are iden- 

 tical ; they are not true Cyprina, but Cytherece of the Circe group. 

 The Venus pwnila of Lamarck (= Cyt. Cyrilli, Scacchi) is only a 

 varietal form. 



On Cytherea (p. 95). C. pellucida (p. 101) is figured in Sow. Th. 

 2, t. 130, f. 190, and C. umbonella (p. 102) at t. 130, f. 64, 66 of the 

 same work. Should the C. cygnus of Sowerby be identical with ours 

 (p. 109), the Mediterranean locality is, to say the least, uncertain. 

 For additional species consult the monographs by Sowerby (Th. Con.), 

 and Deshayes (British Museum Catalogue). Examine, likewise, 



2 e 



