118 Mr. J. Lubbock on two new species 0/ Calanidae. 



The first pair of maxillipeds j^. 



The second pair of maxillipeds y^^. The palpus is -^-^ in 

 length^ 4-jointed and tapering towards the apex ; the other 

 species of the genus have six segments to the palpus^ and the 

 joints which have disappeared are the two apical. The basal 

 segment has a number of spines or small teeth on the inner 

 edge. L. magna agrees with the present species in having also 

 a few spines in the same place. In the arrangement and struc- 

 ture of the hairs, this organ agrees almost exactly with that of 

 L. magna, except that the third hair has no spines above. 



The third pair of mandibles ^-q. 



Thoracic legs. The iirst four pairs are adapted for swimming, 

 as in the rest of the family, and are all alike, except that they 

 increase in size from the first to the fourth, which are gV i^ 

 length. The large spines on the external margin of each leg are 

 dentated above, and accompanied by a smaller spine on each 

 side. All the appendages, from the second pair of antennae to 

 the fourth pair of thoracic legs inclusive, are very similar to 

 those of the allied species. 



The fifth and last pair is very difi'erent ; its use in swimming, 

 if any, is quite subordinate to its functions connected with the 

 act of fecundation. In the female they are smaller and simpler 

 than in the male, and symmetrical, while in the latter they are 

 much more complicated, stronger, and asymmetrical, the right leg 

 being the largest and forming a prehensile apparatus. 



In the present species these legs of the female (fig. 4) are much 

 larger than in L. Darwinii or Patagoniensis, measuring -Jjj in 

 length. They most nearly resemble those of L. Darwinii, from 

 which they only differ in their larger size, and in the external 

 branch being longer and bearing three instead of two spines at 

 the extremity. 



The left leg of the male (fig. 3) consists of four joints as in 

 the other species, but the second segment (counting from the 

 base) appears both in this and in the corresponding right leg to 

 be composed of two which have coalesced. It most resembles 

 that of L. Darwinii, and, like it, bears two rami. I have already 

 remai'ked the curious relation which appears to exist between this 

 branch and the prehensile spine of the right male antenna, viz. 

 that where one is developed the other disappears, and vice versa. 

 This ringed branch is homologous with the inner ramus of the 

 other thoracic legs, like which it is two-jointed. In the present 

 species it is long, slender, tapering, and ringed, with the rings 

 produced into papillae. Like the corresponding organ of L. Dar- 

 winii it appears to be extensible, as the length and thickness 

 vai'y in difi^erent specimens. Length ^\y' 



The right leg, ^^^ (fig. 3), also consists of four joints, but, as in 



