NEW AND RARE SPECIES OF COPEPODA FROM SCOTLAND 29 



on the 25th of January 1894: there were several specimens 

 of this form. On the 2Oth of August following, three species 

 (two of which are described here), apparently belonging to 

 the same genus, were obtained in the Forth, near Mussel burgh 

 they were taken in pools on the shore, near low -water 

 mark ; but these three species, though similar in habit and 

 in general structure to the one obtained west of Oueensferry, 

 and for which the genus Leptopsyllus was instituted, differ 

 from it in the following points: ist, the mandible-palp is 

 two -branched instead of one -branched the distal branch 

 being two-jointed, while the proximal branch, which is smaller, 

 is one -jointed ; 2nd, the second and third pairs of swim- 

 ming feet are two-branched the inner branches, which are 

 one or two-jointed, being more or less rudimentary. But 

 notwithstanding these and one or two other minor differences, 

 the Musselburgh species are, in our opinion, undoubtedly 

 congeneric with that from west of Queensferry, and we there- 

 fore prefer to amend the generic definition as published in 

 part iii. of the " Twelfth Annual Report of the Fishery 

 Board for Scotland," rather than establish a' separate sub- 

 genus for them. The definition of the genus Leptopsyllus 

 as amended will therefore be as follows x : 



LEPTOPSYLLUS (amended), T. Scott, " Twelfth Annual 

 Report of the Fishery Board for Scotland," part iii. p. 253 

 ( i 894). Body elongate, cylindrical, somewhat similar in form 

 to Cylindropsyllus, Brady. Anterior antennae (in the female, 

 seven or) eight-jointed, short. (In the male the anterior 

 antennae are modified and hinged for grasping.) Posterior 

 antennas three-jointed ; secondary branch small, one-jointed. 

 Mandibles well developed, the broad biting part armed with 

 several strong teeth ; palp comparatively large, consisting of 

 a single two-jointed branch (or of two branches the distal 

 branch being two-jointed, while the proximal branch, which 

 is smaller, is one-jointed). Other mouth appendages as in 

 Cletodcs, except that the posterior foot-jaws are three-jointed. 

 Both branches of the first pair of swimming feet short, two- 

 jointed. In the second and third pairs the inner branches 

 (are one or two-jointed and more or less rudimentary, or) 



1 The Amendments are within ( ). 



