12 THE ATLANTIC. [chap. i. 



Several examples of a large and liandsonie species of the genus 

 Scaljpellum came np in the trawl, a few still adhering to some 

 singular-looking concretionary masses which they brought up 

 along with them, 



Scalpellwm o'egium (Fig. 2) is one of the largest of tlie known 

 living species of the genus. The extreme length of a full-sized 

 specimen of the female is 60 mm., of which 40 mm. are occu- 

 pied by the capitulum and 20 ram. by the peduncle. The capit- 

 ulum is much compressed, 25 mm. in width from the occludent 

 jnargin of the scutum to the back of the carina. The valves 

 are 14 in number ; they are thick and strong, with the lines of 

 growth strongly marked, and they ht very closely to one an- 

 other, in most cases slightly overlapping. When living, the ca- 

 pitulum is covered with a pale-brown epidermis, with scattered 

 hairs of the eame color. 



The scuta are slightly convex, nearly once and a half as long 

 as broad. The upper angle is considerably prolonged upward, 

 and, as in most fossil species, the centre of calcitication is at 

 the upper apex. A defined line runs downward and backward 

 from the apex to the angle betw^een the lateral and basal mar- 

 gins. The occludent margin is almost straight ; there is no 

 depression for the adductor muscle, and there is no trace of 

 notches or grooves along the occludent margin for the recep- 

 tion of the males; the interior of the valve is quite smooth. 

 The terga are large, almost elliptical in shape, the centre of cal- 

 cification at the upper angle. The carina is a handsome plate, 

 very uniformly arched, with the umbo placed at the apex ; two 

 lateral ridges and a slight median ridge run from the umbo to 

 the basal margin ; the lower part of the valve widens out rapid- 

 ly, and the wdiole is deeply concave. The rostrum, as in Scal- 

 pellum vulgare, is very minute, entirely hidden during life by 

 the investing membrane. The upper latera are triangular, the 

 upper angle curving rather gracefully forward; the umbo of 

 growth is apical. 



