SUBEMARGINULA. 277 



Front rib strongest, ending in a notch ; surface latticed by the 

 concentric cords crossing the radiating riblets ; of the latter every 

 third one is larger, these principal ones 12 in number, including 

 three large front ribs; a smaller riblet in each internal, and on 

 each side of these a minute one. Interior bright green, a small 

 central patch and the border white. Margin crenulated. 



Length 21, breadth 14, alt. 12 mill. 



Tonga Tabu, S. Pacific; Philippines. 



Patella tricarinata BORN., Test. Mus. Cses. Vindob. p. 423, t. 18, 

 f. 6. Not Patella tricarinata Linn. Emarginula panhi QUOY & 

 GAIMARD, Voy. de 1'Astrol. 327, t. 68, f. 7, 8. Sabemarginula pan- 

 hiensis A. AD., P. Z. S. 18ol, p. 90. E. panhiensis SOWB., Thes. p. 

 218, f. 73, 74, 75. E. clathrata ADS. & REEVE, Voy. Samarang, p. 

 69, t. 11. f. 6, 1850. 



A very distinct species. This genus is already in such terrible 

 confusion that the inevitable restoration of Born's name to this shell 

 is a very slight additional embarrassment. 



S. OLDHAMIANA Nevill. ' PI. 41, figs. 32, 33. 



Shell small, obliquely conical, the apex twisted to the right and 

 backward. Surface bearing strong radiating ribs with smaller 

 interstitial riblets, the principal ribs about 8 in number, somewhat 

 nodose ; interior yellow or green-tinged, the anal groove deep, green, 

 notch short. Length 10, breadth 7, alt. 4 mill. 



Ceylon. 



E, oldhamiana NEVILL, Journ. Asiat. Soc. Beng. xxxviii, p. 162, 

 t. 17, f. 17. 



A curiously twisted little species, allied to S. tricarinata Born. 



S. IMBRICATA A. Adams. PI. 29, figs. 14, 15. 



Ovate-oblong, subquadrangular, ashy-white, vertex small, central, 

 inclined backward; decussated with imbricated, unequal radiating 

 ribs and thick irregular growth-lines ; margin of the aperture den- 

 tate, deeply sinuate in front, sinus subquadrate, produced in a canal 

 within. (Ad.) 



Mouth of Victoria River, N.-E. Australia, under stones at low 

 water. 



S. imbricata AD., P. Z. S. 1851, p. 91. E. imbricata SOWB., Thes. 

 p. 217, f. 70, 71. 



