of the Fishery Board for Scotland. 471 
Pseudopsyllus, T, Scott (gen. nov.). 
Somewhat like Clausia, Claparéde, in general appearance ; the abdomen 
scarcely distinct from the thorax ; antennules composed of six short but 
stout joints. The antenne are somewhat similar to those of Herszliodes, 
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.). Pl. XXIV., figs. 36-42. 
Description of the Female.—Length 1:4 mm. (,4 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°,18 
Numbers of the joints, - ae ect, Aen ee.S 1G 
The antenne 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 
sete, 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 sete; 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 sete on its inner margin instead of one, while the end 
joint bears only three apical seta, instead of four sete and an elongate 
Spine as in the first pair (fig. 41). 
