473 



small spinnle. Colour, according to the figure given by Sp. Bate, whitish with 

 red spots. Length of adult female reaching 30 mm. 



Remarks. This is the form upon which Leach founded his genus 



Atylus. It was first described in the year 1793 by Fabricius as Ganniiiirii* 

 car hiatus, and was subsequently redescribed by Kroyer as a new species of 

 the genus Ampliitlioe, the very same specific name being applied. Though 

 somewhat resembling in its general appearance, certain species of the genus 

 Parfitiiln*, for example the P. norcllandicns. it is, however, easily distinguished, 

 not only by its large size, but also by the far less slender antennae, the 

 comparatively more robust structure of the gnathopoda, and the want of 

 the dorsal notch on the 1st segment of urosome. 



Occurrence. - - The only true evidence of the occurrence of this arctic 

 form off the coast of Norway, is derived from a single, but rather well- 

 preserved specimen, which was extracted by Prof. Collett from the stomach 

 of a Liparis Montagu! captured at Tromso, Finmark. As the Lipari may be 

 regarded as rather stationary fishes, we are fully justified by the above- 

 stated fact in including the form among the fauna of Norway. On the other 

 hand, the correctness of Prof. Lilljeborg's statement about the occurrence of 

 this form as far south as Molde, west coast of Norway, seems to me to be 

 highly questionable, and I am much inclined to believe that he has in this 

 case mistaken Paratylus nordlandicus for the present form. 



Distribution. - - Arctic Ocean: Greenland (Fabr.), Spitsbergen (Goes), 

 Franz Josephs Land (Miers), the Murman coast (Jarzynsky), the Kara Sea 

 (Stuxberg), the Siberian Polar Sea (Stuxberg). 



Gen. 3. Dexamine, Leach, 1814. 



Syn. : Ampbitbonotns Costa (part). 



Body comparatively stout, and not much compressed, with some of the 

 segments elevated to strong dorsal projections. Urosome of much the same 

 structure as in the 2 preceding genera, having the 2 outer segments com- 

 pletely fused together. Cephalon of moderate size, with a small rostral 

 projection, and the postantennal corners quite obsolete. Coxal plates of middle 

 size, and increasing in depth to the 4th pair, which are evenly emarginated 

 posteriorly; 5th pair rather broad, and much larger than the succeeding pairs. 

 Eyes well developed, and placed close to the anterior edges of the cephalon. 

 Antennae very slender, the superior ones with the peduncle much elongated, 



62 Crustacea. 



