NO. 1580. NEW SPECIES OF CALK ilN.E— WILSON. 619 



about opposite the tip of the mouth tube, so as to be freely movable, 

 which is not the case in the genera just named. Moreover, the large 

 papilla tipped with two spines and representing the rudimentary 

 endopod, is in this case borne, not on the base of the exopod, but 

 on the ventral surface of the carapace anterior to the joint. We have 

 in these maxilla^, therefore, a basal joint fused to the surface of the 

 carapace upon which is borne a freely movable exopod, the maxilla 

 itself, and a rudimentary endopod much larger than usual. 



The mouth tube is similar to that found in Caligus. As will be 

 seen from fig. 83 the bony framework is more nearly like that of 

 Lepeophtheirus Mppoglossi than of any other species yet descrilied, 

 while the mouth opening itself is like that in Caligus rapax. There 

 are rods running along either side of the mouth tube, with their 

 proximal ends turned downward and outward toward the ventral 

 surface just as in L. hippoglossi."^ To these are attached near the 

 base of the tube a pair of short rods arranged like the sides of the 

 letter V, with the point turned toward the tip of the tube instead 

 of toward the base as in C. rapax. Between the tips of these lateral 

 rods in the lower lip is a series of small transverse rods similar to 

 those in C. curtus. And the upper lip also ends in a soft flap like that 

 in C. curtus and L. edwardsi, but not of the same shape. 



Inside the mouth tube may be seen the mandibles, which are nar- 

 row, curved strongly at the tip, and toothed along the concave margm. 

 The first maxillipeds are of the usual pattern, the two joints about 

 the same length, the inner terminal claw twice the length of the outer, 

 and both claws well curved. The second maxillipeds are com- 

 paratively weak, smaller, or at least no larger, than the second anten- 

 nae, with a terminal claw little more than half the length of the basal 

 joint. This claw is not much curved and carries a slender accessory 

 seta on the inside near its base. 



The furca is peculiar in two respects ; the furca itself is double and 

 its branches are bifurcate. Kroyer reports a species of Caligus (C. 

 fallax) in which the furca is double, while there are at least three 

 species of Lepeophtheirus in which the branches are bifid {L. Mppo- 

 glossi, rohustus, and hifurcatus). 



The present species, so far as known, is the first to show a combi- 

 nation of the two. But it does not show two complete furcae, as 

 Kroyer figures for C. fallax, neither is the division of the branches 

 anything like that of the three Lepeophtheirus species named. The 

 median sinus of this furca is broadly U-shaped ; each branch is divided 

 for about half its length, the inner branchlets parallel and forming 

 the sides of the U, the outer one turned almost at a right angle. Both 

 pairs of branchlets are broad, of the same diameter throughout, and 

 with bluntly rounded ends. On either side of the base of the furca 



aProc. U. S. Nat. Mus., XXVIII, p. 500, lig. 6a. 



