oj the Fishery Board for Scotland. -471 



Pseudopsyttus, T. Scott (gen. nov.). 



Somewhat like Clausia, Claparede, in general appearance ; the abdomen 

 scarcely distinct from the thorax ; antennules composed of six short but 

 stout joints. The antennae are somewhat similar to those of Hersiliodes, 

 Canu. Second maxillipeds apparently two-jointed, and armed with ex- 

 tremely long and powerful terminal claws ; other mouth organs unknown. 

 The first four pairs of thoracic feet have both branches three-jointed as in 

 Hersiliodes. Fifth pair short, and composed of a single lamelliform joint. 

 Male unknown. 



Pseudopsyllus elongatus, T. Scott (sp. nov.). PI. XXIV., figs. 36-42. 



Description of the Female. — Length 1*4 mm. (-^ of an inch). Body 

 elongate-narrow ; when viewed from above the anterior thoracic portion 

 is slightly broader than the abdomen, but the distinction between thorax 

 and abdomen is not very marked (fig. 36). The cephalo-thoracic segment 

 is about equal to the entire length of the next four ; rostrum short. 



Antennules very short and stout and composed of six sub-equal 

 joints ; moderately setiferous and provided -with three sensory fila- 

 ments — one on the fourth joint, one on the fifth, and one on the end 

 of the last joint (fig. 37). The formula shows approximately the lengths 

 of the different joints ; — 



Proportional lengths of the joints, 15 ' 11 ' 9 ' 12 ' 10 ' . 13 

 Numbers of the joints, - 1 • 2 * 3 • 4 • 5 • 6 



The antennae are small but moderately stout, the first joint is the 

 largest, the second and third are small, while the fourth is nearly as long 

 as the second and third combined • the exterior angle of the joint 

 extends forward to near the middle of the end joint and terminates in a 

 small spine ; the end joint seems, for the reason just stated, to arise from 

 slightly beneath the penultimate one, somewhat similar to the structure 

 of the same appendages in species of Hersiliodes (fig. 38). 



The second maxillipeds — the only mouth organs obtained — are robust 

 and armed with long and powerful terminal claws (fig. 39). 



The first four pairs of thoracic feet are stout, moderately elongated, 

 and with both branches three-jointed and of nearly equal length. In the 

 outer branches of the first pair (fig. 40) a stout and moderately long spine 

 springs from the outer distal angle of the first and second joints, while 

 the end joint carries three similar spines on the outer margin and apex ; 

 a plumose seta springs from the inner margin of the second joint, and five 

 from the inner margin and apex of the last joint ; the first and second 

 joints of the inner branches are each provided with one plumose seta on 

 the inner margin, while the end joint carries two marginal and two apical 

 setae, in addition an elongate spine which springs from its outer distal 

 angle. In the fourth pair the armature of the first and second 

 joints of the outer branches is similar to that of the first and second joints 

 of the outer branches of the first pair except that the marginal spines are 

 not so elongated ; but the armature of the end joint differs from that of 

 the same end joint of the first pair in that it carries only one small spine 

 on the distal half of the outer margin and a moderately long but slender 

 sub-apical spine, while round the inner margin and apex there are six 

 instead of five plumose setae ; the armature of the inner branches differs 

 from that of the inner branches of the first pair, the second joint is pro- 

 vided with two setae on its inner margin instead of one, while the end 

 joint bears only three apical setae, instead of four setae and an elongate 

 spine as in the first pair (fig. 41). 



