of the Fishery Board for Scotland. 



153 



sub- triangular, and have three small terminal hairs arranged as shown on 

 the figure. 



Figure 8 represents a young specimen newly hatched. 



Lepeophtheirus pollachii, Basset-Smith. (PI. VI., figs. 9-15.) 



1896. Lepeophtheirus pollacMus, Basset-Smith, Ann. and Mag. 



Nat. Hist. (6), vol. xviii., p. 12, PI. IV., fig. 1. 

 1899. Lepeophtheirus pollachii, Basset-Smith, Proc. Zool. Soc, 



Lond. (April 1899.) 



The length of the specimen represented by the drawing (fig. 9) is about 

 three -tenths of an inch (7*5mm.). The cephalic shield is sub-orbicular, 

 but the last segment of the thorax is sub-quadrate, and is nearly as large 

 as the cephalic shield ; this segment also slightly increases in width 

 towards the posterior end. The abdomen is about as long as the last 

 thoracic segment, and tapers somewhat towards the extremity. The 

 caudal segments are of moderate size. 



The antennas are armed with moderately large terminal claws strongly 

 hooked at the end. The mandibles are elongate and slender ; the last 

 joint, which is short and about as broad as thepreceding one, is serrated 

 on the inner edge. The sternal fork has moderately short and simple 

 divergent branches, and resembles the letter V inverted (fig. 13). The 

 posterior foot- jaws are stout, and provided with strong terminal claws. 

 The branches of the fourth pair of thoracic feet, which are three-jointed, 

 are moderately elongated and slender • three spiniform setae spring from the 

 end of the third joint, while the first and second joints are each provided 

 with a seta or spine on the outer distal angle (fig. 15). The fifth feet are 

 small, sub-quadrate, and bear each three small apical setae. 



The male is about as Jong as the female, but the last segment of the 

 thorax is very small ; the abdomen is composed of tw r o sub-equal segments 

 (fig. 10). The antennae and the posterior foot-jaws of the male also 

 differ to some extent from those of the female. 



Ho.bitat. — Our specimens were obtained adhering to the inside of the 

 mouth of a lythe, Gadus pollachivs, caught in the salmon-nets in Bay of 

 Nigg, Aberdeen, June 22nd, 1899. 



This species appears to develop moderately long ovisacs. 



(2) Abdomen composed of two segments. 

 Lepeophtheirus (?) obscurus Baird. (PI. VL, figs. 16-19.) 



1850. Lepeophtheirus obscurus, Baird, Brit. Entom., p. 277, 



PI. XXXII., fig. 11. 

 1896. Caligus obscurus, Basset-Smith, Ann. and Mag. Nat. 



Hist. (6), vol. xviii., PI. IV., fig. 2 ; Journ. M. B. Assoc. 



Plymouth (1896), p. 157. 

 1899. Lepeophtheirus obscurus, Basset-Smith, Proc. Zool. Soc. 



Lond. (April 1899), p. 456. 



The length of the female specimen represented by the drawing (fig. 16) 

 is about one-fourth of an inch (8'2mm.). The cephalic shield is sub- 

 orbicular, but rather longer than broad. The last segment of the thorax is 

 about two-thirds of the length of the cephalic shield, and of a sub- 

 cylindrical form, and its posterio-lateral angles are produced into boldly- 

 rounded lobes. The abdomen is in length equal to about three-fourths of 

 the length of the last segment of the thorax, and is distinctly jointed near 

 the posterior end. The caudal segments are very small. 



The antennae are armed with large and strongly-hooked terminal claws 



