238 Part III. — Twelfth Annual Report 



outwards, bears two distinct one-jointed branches on the exterior margin 

 (fig. 14). Anterior foot-jaws four-jointed, with the basal joint very large 

 comparatively, and the end joints small ; the second joint is produced 

 interiorly so as to form a base for a stout curved spine (fig. 15). Posterior 

 foot-jaws elongate, seven-jointed, the last five joints small, their entire 

 length being very little greater than the length of the second joint (fig. 

 16). Swimming-feet robust, both branches three-jointed. The marginal 

 spines of the outer branches of the first pair are large and dagger-shaped, 

 and project at, or nearly at, a right angle to the outer margin. Those of 

 the fourth pair are much smaller, but the marginal setae on both the 

 outer and inner branches, but especially on the inner branches, are stouter 

 than the marginal setae of the first pair. In the first pair, also, a stout 

 spine springs from the inner distal margin of the second basal joint, and 

 projects downwards beyond the end of the second joint of the inner 

 branches (fig. 17). Fifth pair stout, each consisting of a single three 

 jointed branch. The breadth of the first two joints is greater than the 

 length ; while the third joint is longer than broad, being equal to the 

 entire length of the first two. The first joint bears a moderately long 

 plumose seta on the outer distal angle. The second joint bears a similar 

 seta on the inner distal angle, while the last joint bears two plumose setae 

 on the inner margin, and one plumose seta and a dagger-shaped spine at 

 the apex (fig. 19). Caudal stylets elongate, being equal to the combined 

 length of the last two segments of the abdomen ; and, in addition to the 

 terminal setae, each of the stylets bears one small hair near the proximal 

 end, and another near the distal end of the outer margin. In the male 

 the anterior antennae are sixteen-jointed, the last six being more or less 

 modified for grasping ; the eleventh joint is comparatively robust and 

 hinged to the preceding one. There is also a hinged articulation between 

 the penultimate and ante-penultimate joints (fig. 11). 



Habitat. — Off St Monans. Rather rare. 



Remarks. — The species now described differs in some important points 

 from any other Gyclopina recorded from the British seas. It resembles 

 Cyclopina littoralis in the form of the fifth pair of thoracic feet, but the 

 proportional lengths of the joints of the anterior and posterior antennae, 

 and the structure of the first pair of swimming-feet, are decidedly different. 

 It also, in this respect, differs from Cyclqpina ovalis, Brady ; while the 

 shorter and much fewer jointed anterior antennae of Cyclopina gracilis, 

 Claus, readily distinguish that species from the one now described. 



Genus Pterinopsyllus, Brady (1880). 



Pterinopsyllus insignis, Brady. 



1878. Lophophorus insignis, Brady (8), vol. i. p. 122, pi. xiii. 

 figs. 1-10 ; pi. xv. fig. 10. 



1880. Pterinopsyllus insignis, Brady (8), vol. iii. p. 23. (Lopho- 

 phorus being preoccupied, Dr Brady substituted the word 

 Pterinopsyllus for this genus). 



1893. Pterinopsyllus insignis, T. and A. Scott (32), p. 243. 



Habitat.— -West of Queensferry. Frequent. This beautiful species has 

 several times been obtained in the part of the Forth estuary referred to. 

 In this part of the Forth there are periodic and very marked variations 

 in the salinity of the water ; caused on the one hand by the ebb and flow 

 of the tide, and on the other by the large volumn of fresh water from the 

 river, which, forced back by the flowing tide, accumulates in the upper 

 reaches, and, when the reflux takes place, rushes seawards with over- 

 powering force, so that, during the later part of the ebb, and the early part 



