48 ACM^EA. 



A number of specimens of this form are before me. They differ 

 from A. borneensis Rv. only in being more distinctly striated and 

 darker colored. The largest specimen. I fcave seen measures, length 

 43, breadth 39, alt. 9 mill. 



VAR. BORNEENSIS Reeve. PI. 35, figs. 25, 26, 27, 28, 29. 



Shell rounded -oval, rather thin, depressed, the apex at about the 

 anterior third ; slopes convex ; surface nearly smooth, but obscurely 

 radiately striated ; dull-grayish-white with close hair-like radiating 

 black lines and more or less speckled with brown or blackish, these 

 last markings frequently forming obscure darker rays ; sometimes 

 blackish all over. 



Inside bluish-white, with a wide dark border and a small brown 

 central area. Muscle-scar inconspicuous, remote from the margin. 



Length 29, width 24, alt. 7 mill. 



Amboyna ; North Coast of Borneo. 



P. borneensis Rv. Conch. Icon. f. 113, 1855. Collisella borneen- 

 sis DALL, Amer. Journ. Conch, vi, p. 259, t. 15, f. 17 (dentition) ; t. 

 17, f. 38 (shell). A. Bickmorei DALL mss. 



A depressed species, nearly smooth, hair-lined with deep brown 

 or black and more or less speckled with the same color. I have 

 seen none with the rays so pronounced as in Reeves figure. 



A. FLUVIATILIS Blanford. PI. 35, figs. 40, 41, 42. 



Shell much depressed, conical, subcircularly oval, thin, covered 

 with a very dark olive epidermis, always eroded at the subcentral 

 apex ; marked with fine radiating raised lines, and with close and 

 minute concentric striae of growth. 



. Inside the shell is bluish-white, sometimes with one or more 

 milky concentric bands, or the whole interior is milky, except the 

 cavity of the apex which is invariably ferruginous. (Blanf.) 



Length 2H, breadth 20, alt. 6 mill. 



Length 20, breadth 17, alt. 5-1 mill. 



Length 14, breadth 12, alt, 4 mill. 



Delta of the Irawadi River, Pegu. 



Tectura fluviatilis W. T. BLANFORD, Journ. Asiatic Soc. Bengal, 

 xxxvi, pt. 2, 1867, p. 62, t. 13, f. 2, 3, 4 (1868). 



This species is found on rocks, rarely on trunks of trees, in many 

 of the creeks near high-water mark, in brackish water. It was not 

 met with near the sea, where the water was very salt. The foot is 



