461 Dr. T. Scott on British Copepoda. 



additional terminal seta on the outer branch ; 3rd, the inner 

 branch of the third pair is provided with an elongated slender 

 spine, which springs from the base of the branch and extends 

 to beyond the apex ; 4th, the abdomen is five-jointed ; and, 

 5th, the smaller size of the fifth pair of feet. The female 

 carries only one ovisac. 



Though Evansia has a close resemblance to Tetragoniceps, 

 it is at once distinguished by the small uniarticulate inner 

 branches of the second, third, and fourth thoracic feet. 



Type species Evansia incerta, T. Scott. Described under 

 the name of " Tetragoniceps incertus, T. Scott/' in the ' Tenth 

 Annual Report of the Fishery Board for Scotland/ pt. iii. 

 p. 254, pi. xii. figs. 1-17 (1892). 



A second species was described under the name of " Tetra- 

 goniceps pygmams, T. Scott/' in the ' Twenty-first Annual 

 Report of the Fishery Board for Scotland/ pt. iii. pi. iv. 

 figs. 11-19 (1903). This species, as pointed out in the 

 description, agrees with E. incerta in all its more important 

 characters, as, for example, in the structure of the thoracic 

 legs in the female, and only shows some minor differences 

 sufficient for the separation of the two species. This species 

 will now be known as Evansia pygmcea, T. Scott. 



Genus Leptastacus, T. Scott, no v. 



Description. — Body elongated, slender. Anterior antennae 

 in the female eight-jointed and wanting the hook-like spine 

 observed in the same appendages in Tetragoniceps and 

 Evansia. Posterior antennae three-jointed; outer ramus 

 rudimentary. Mandible and mandible-palp as in Evansia. 

 First maxillipeds small, provided with two bilobed setiferous 

 processes and a moderately stout terminal spine. Second 

 maxillipeds slender and armed with an elongated and slender 

 terminal claw. Inner branches of all four pairs of thoracic 

 legs two-jointed and the outer three-jointed. In the first 

 pair the inner branches are considerably longer than the outer, 

 and the two joints are of nearly equal length. In the next 

 three pairs the inner branches, which, like those of the first 

 pair, are composed of two nearly equal joints, are much 

 shorter than the outer. Fifth pair very small and uniarti- 

 culate, they have each a narrow triangular outline and taper 

 gradually to the pointed apex. The abdomen is composed of 

 four segments. One ovisac containing a few tolerably large 

 ova. 



The male does not differ greatly from the female, but the 

 anterior antennas are nine-jointed and modified for grasping. 



