288 BAENACLES *BOM DEEP-SEA CABLES. 



Inframedian. The inframedian latus is comparatively large 

 and of broadly triangular form. Its base forms an acute angle 

 anteriorly with that of the carinal latus. The posterior angle 

 dives beneath the carina and is truncate; the anterior angle is 

 somewhat produced below the base of the scutum. 



Carinal latera. The carinal latus is also triangular, but more 

 symmetrical, more produced at the anterior and posterior angles 

 and with its base parallel to that of the capitulum and its apex 

 pointing directly upwards between the upper latus and the carina. 

 The base of the valve is buried in the cartilaginous investment but 

 the apex projects outwards almost to the surface. 



Rostral latera. The rostral latus resembles the carinal latus 

 in shape and orientation but is even more transverse and is con- 

 siderably produced backwards, extending for some distance below 

 the base of the latter valve. 



Carina. The carina is of moderate size. It extends upwards 

 very little beyond the apex of the scutum and falls far short of 

 that of the tergum. Viewed from the side it is narrow and tapers 

 gradually to the apex ; its upper half has a distinct but by no means 

 strong curvature and the apex projects very little behind the pos- 

 terior margin of the tergum. The base is convex downwards. The 

 dorsum is obscurely carinate and slopes outwards on either side. 

 The base is subangulate and the apex sharply pointed. 



Subcarina. The subcarina, which projects almost directly 

 backwards but extends very little behind the carina, is broadly 

 triangular and of comparatively large size. Its apex lies below 

 the middle of the base of the carina and between the posterior 

 angles of the carinal latera. 



Bostrum. This valve resembles the subcarina closely but is a 

 little larger and has its apex retroverted below the base of the 

 capitular orifice. It projects hardly at all. 



Peduncle. 



The peduncle is stout, somewhat compressed and distinctly 

 constricted in the middle. It is of a pale brown colour and a 

 cartilaginous consistency. The surface is wrinkled transversely and 

 divided into small areas, which on the lower part are transverse 

 and rhomboidal, by a network of minute grooves. To the naked 

 eye the capitulum appears to be quite unarmed, but a lens reveals 

 numerous microscopic calcareous particles embedded in the mem- 

 brane. They have a spindle-shaped or oval outline, are flattened 

 and for the most part directed outwards but do not penetrate the 

 surface. Their position is not correlated with that of the areas 

 on the surface, which are perhaps of artificial origin. 



Cirri, etc. 



1st Cirrus. Both rami are slender and tapering, without di- 

 lated segments, the anterior ramus is considerablv the shorter of 



Jour. Straits Branch 



