608 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxxiii. 



The second antennae have a stout' basal joint with a long and 

 slender terminal hook. The mouth tube is about twice as long as 

 wide, with the mouth opening circular, subterminal (a little more on 

 the ventral side), and surrounded with a fringe of long hairs. The 

 tube is constricted somewhat sharply on either side at about the cen- 

 ter. The details of the bony framework supporting the lower lip are 

 shown in Fig. 58, and of course differ from those shown in other genera 

 of the Caliginse. 



There are first at the base a pair of long and wide bones (a) flat- 

 tened dorso-ventrally, Ijdng side by side along the mid line. 



At their proximal ends these bones articulate with the ventral 

 surface of the carapace, at their distal ends with two other pairs of 

 bones {h) much smaller and cylindrical, also lying along the median 

 line. The distal ends of this last pair articulate with the curved 

 bones {c) surrounding the mouth. Outside the first pair are two 

 irregular bones {d) on either side along the lateral margin; outside 

 the second pair a single triangular bone {e) on either side, its broad 

 base articulating with the distal ends of the first median pair and the 

 marginal bones outside of them, its apex joining the bony framework 

 around the mouth close to the distal ends of the second median pair. 



Still outside of these triangular bones and along the lateral margin 

 of the distal portion of the lip is a long bone curved outward quite 

 strongly (f ) . The proximal end of this bone articulates with the outer 

 proximal angle of the triangular bone just at the constriction in the 

 lateral margin of the lip. Its distal end is bifid, the two branches 

 joining the sides of the bony circle around the mouth. 



The entire bony framework of the lip is thus definitely jointed along 

 a line joining the constrictions in the lateral margins of the lip. This 

 jointing constitutes the most essential difference between the structure 

 of the tube in the present genus and that in Caligus and Lepeoplitlidrus. 



The mandibles inclosed within the tube are similar to those in the 

 two genera named. They are curved in toward each other at their 

 tips, with coarse teeth along the inside of the curve and fuier ones 

 along the outside. 



The first maxillaB are close to the tips of the second antennae; they 

 are rather small, with swollen bases and naiTow, elongate, and blunt 

 tips. The second maxillae lie close to the mouth tube; they are 

 simple and triangular, with broad bases and short, stout tips, slighth^ 

 curved. From the ventral surface of the base arises a stout papilla^ 

 representing the endopod and tipped with two setae. The outer of 

 these is tliree times the length of the inner one and is jointed once 

 near its base. 



The first maxillipeds are like those usually found in the Cahginae ; 

 the second pair have a large and stout basal joint furnished with pow- 

 erful muscles and a long, slender, and strongly curved terminal claw. 

 There are upon the inner surface of the basal joint a pair of stout 



