BNO4 HOT 



7 in. central valve- I -lit. 'I 



wide, ll:ii. ( iirdle lurid-lied \\ ith \ . 



tened M-ales. Length 10, width .') mill.; di\< 



(.'iKi'l.l/nllf,,- . Mil ' 



( >ne specimen Is of a pale yellowish tint flight]} -I \\iih :i 



brighter color; another i- in .iv a-hy and \vil li t lie \ : 

 pale olive. h has stronger .-culpture than /. <//, //,/,*/,,///;/. 

 ruguhe rising tij) like close rungs in a rope-ladder, and denta' 

 the sutures. ( ( '/-.') 



The above deseri|>t ion, from Carpenter 1 ! .!/>. defioei a fonn 

 which will probably prove to he a variety of T.cwil 

 \\hieh species Carpenter, at a later date, united it. 



I. PBUINOSU8 Could. IM. LM, fitrs. 27, 28. 



Shell small, elongated, nearly elliptical, convexly elevated, 

 earinate. or rather somewhat doubly carimite alon^ tlie hack : or 

 t'aee generally covered with microscopic |)iinetnres, ai-raiiL r fd in 

 lo/.'.-ni:e. Lateral areas very slightly rair-cd, and longitudinally 

 imbricate-sulcate ; central areas with faint line wth and 



punctures in quincunx ; anterior valve concentrically .-triate, not 

 punctate; posterior valve slightly nmbonate, and rn-> ed ly a 

 Iran-verse ridge, behind which it is concentrically Mriate. 1 

 frosted or mottled with dark brown, ash, purple, green. Are. Mar- 

 gin minutely granulated, so as to look hoary. (Old.) 



"Some specimens are of a uniform pale green. Margin chmdrd 

 with dark green; some had two or three distinct, white blotch. 

 the sixth valve, the rest of the shell being olive-green, with a line 

 of faint green along middle of back ; another had the ground-colour 

 a clear olive, three dark brown spots bordered with white <>n each 

 side of posterior margin of valves, a row of similar spot- surround- 

 ing the terminal valves just above insertion, and the whole sin 

 sparsely and irregularly spotted in the same way nt a 



delicately mottled a-pect. A fourth variety wa> of a uniform dark 

 rosr-oilor. and the margin clouded with dark red band<. Inter- 

 nally it was dark red or rosy along the middle, and dull yellow 

 toward- the sides. All the other varie. i greenish 



hue internally." (Cnnfli. i,, <;!<!. > 



Length 17 '. breadth * ; mill. 



Off /''"' s '"" / " OrVft H'" /"""''", "" stone- in 'J or :i t'ms. 



