new and rare, Crustacea from Scotland. 51 



discovered in Germany some years ago by Dr. Poppe, but 

 which has not hitherto been known to occur in the British seas. 



Leptopsyllus intermedins, sp. nov. (PI. V. figs. 1-11.) 



Description of the Species. — Female. Length "58 miUim. 

 (jV of an inch). Body elongate, slender. Anterior antennse 

 eight-jointed, short, moderately stout ; the first five joints 

 gradually decrease in length, the fifth and sixth are equal ; 

 the seventh is shorter than any of the others, while the last 

 is equal to tlie combined lengths of the two joints immediately 

 preceding. The antennae are provided with numerous mode- 

 rately long setffi, and a stout hlament springs from the upper 

 distal edge of the fourth joint. The subjoined formula shows 

 the number and proportional lengths of the joints — ■ 



Proportional lengths of the joints . . 22 . 1 3 . 10 . 9 . 6 . 6 . 4 . 10 

 Number of the joints 1 2 3 4 6 67 8* 



Posterior antenna? and mouth-organs somewhat similar to 

 those of Leptopsyllus Rohertsoni^ T. and A. Scott, but smaller; 

 the end joint of the distal branch of the mandible-palp is also 

 proportionally shorter (fig. 4). The outer and inner branches 

 of the first pair of swimming-feet, which are both two-jointed, 

 are nearly of equal length (fig. 5). The second and third 

 pairs resemble those of Leptopsyllus Robertsoni (tig. 6). In 

 the fourth pair the outer branches are two- and the inner 

 branches one-, or indistinctly two-jointed (fig. 7). The basal 

 joints of the fifth pair are coalescent and form together a 

 broad lamelliform plate, subtriangular in outline ; the margin 

 on each side from the apex to the secondary joint is slightly 

 convex, and immediately behind the secondary joints the 

 margins are produced into broad and somewhat rounded 

 lobes, e«ch lobe being furnished with a moderately stout seta,- 

 the secondary joints are very small (fig. 8). Caudal stylets 

 fully twice the length of the last abdominal segment and 

 equal in breadth to nearly half the length ; they are each 

 furnished with a terminal spine nearly as long as the stylet 

 (fig. 10). One ovisac containing a few large ova. 



Mate. The male is similar to the female, except that the 

 anterior antennae are modified and hinged for grasping, and 

 resemble in structure those of Leptopsyllus Robertsoni. The 

 basal joints of the fifth pair of thoracic feet, which are also 

 coalescent, are considerably shorter than those of the female, 

 and terminate in two broadly convex lobes, one on each side 

 of the median line; each lobe is fringed with minute hairs: 

 the secondary branches are very small (fig. 9). 



4* 



