SUBKMAROINUIvA. 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 panlii QUOY & 

 GAIMARD, Voy. de FAstrol. 327, t. 68, f. 7, 8. Subemarginula pan- 

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

 2,18, f. 73, 74, 75. E. clathrata ADS. & REEVE, Voy. Samarang, p. 

 69, t. ll,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.) 



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

 water. 



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

 p. 217, f. 70, 71. 



