506 



13. Pallasiella qvadrisplnosa, (Esmark), Gf. 0. Sars. 



(PI. 178). 



Pallasia cancelloides, var. qvadrisjnnosa, G. O. Sars, Hist. nat. des Crust, d'eau douce de 



Norv6ge, p 68, PI. VI, figs 21—34. 



Syn : Gammarus cancelloides, Lov6n (not Gerstfeldt). 

 > — Kessleri, Dybowsky, var. europsea. 



Body very slender, witli the segments of mesosome produced on eacli 

 side to an obtuse nodiform prominence, the 2 anterior segments of metasome 

 each armed with 2 strong, juxtaposed, subdorsal spines, curved backwards. 

 Cephalon nearly attaining the length of the first 2 segments of mesosome 

 combined, and having on each side, above the base of the inferior antennae, 

 an obtuse umboniform projection, lateral corners evenly rounded. Anterior 

 pairs of coxal plates but little deeper than the corresponding segments, and 

 rather narrow, being noncontiguous in their outer part; 4th pair scarcely as 

 deep as the preceding pair, and obliquely truncated at the tip. Epiraeral 

 plates of metasome obtusely rounded at the lateral corners. Eyes rather 

 convex, and rounded oval in form, pigment very dark. Superior antennae 

 scarcely exceeding in length Vs of the body, 1st joint of the peduncle nearly 

 as long as the other 2 combined, flagellum not nearly attaining the length 

 of the peduncle, and composed of about 16 articulations, accessory appendage 

 scarcely more than half the length of the last peduncular joint, and biarticulate, 

 with the terminal joint the larger. Inferior antennae somewhat shorter than 

 the superior, the last 2 joints of the peduncle nearly equal-sized, flagellum 

 about the length of the last peduncular joint, and 6-articulate. Gnathopoda 

 in female slightly unequal, the posterior ones being somewhat more slender 

 than the anterior, propodos of the latter obpyriform, of the former oblong 

 oval, with the palm nearly transverse. Both pairs in male comparatively 

 more strongly built than in female, but otherwise of a very similar 

 appearance. Pereiopoda rather slender, and having their outer part edged 

 with fascicles of delicate bristles, basal joint of last pair considerably larger 

 than that of the 2 preceding pairs, and regularly oval in form, with the 

 posterior edge fringed with bristles. Last pair of uropoda of moderate size, 

 with the outer ramus fringed with fascicles of slender bristles, inner ramus 

 scarcely more than '/s as long as the outer, and setiferous on the inner edge. 

 Telson subquadrangular in form, a little broader than it is long, and armed 

 on each side with 3 slender spines, posterior incision rather short, terminal 

 lobes narrowly rounded, and each tipped by a slender spine. Colour yellowish 



