212 



soft metasome of this Crustacean, lying, as a rule, somewhat diagonally 

 along the upper face of that part; hence the peculiar twist of its body. The 

 male is generally found clinging to the left side of the metasome of the female, 

 or, in younger specimens, to the ventral face of that division. 



Distribution. — British Isles (Sp. Bate), Kattegat and Skagerak (Copen- 

 hagen Mus.), French coast (Hesse). — 



2. Athelges tenuieaudis, G. 0. Sars, n. sp. 



(PL LXXXIX, fig. 1). 



Specific Characters. — Body of fully grown female very like that of the 

 preceding species, though somewhat more slender, with the anterior incubatory 

 plates more projecting and expanded in a fan-like manner. Metasome compara- 

 tively longer and narrower, being abruptly twisted to the left, terminal 

 piece nearly cylindric in form. Lamellse of pleopoda subequal oblong oval in 

 shape. — Body of young female rather slender, claviform, with the anterior di- 

 vision of the body rounded oval and perfectly symmetrical, metasome slightly 

 turned to the left, very slender, cylindric, and much longer than the preceding 

 part of the body ; terminal piece somewhat flexuous and narrow cylindric in form, 

 apical tubercles well marked. — Adult male comparatively less slender than that 

 of the preceding species, with the metasome abruptly narrowed beyond the base, 

 and obtusely conical at the tip. Young male, still in the Cryptoniscian stage, 

 rather broad, depressed, with the segments of mesosome acutely produced late- 

 rally; uropoda of a similar structure to that in the corresponding stage of Phryxus 

 abdominalis. Colour not yet ascertained. Length of fully grown female 11 mm., 

 of male 2.20 mm. 



Remarks. — The fully grown female of this species looks very like that 

 of A. pagnri, and is twisted and deformed in a very similar manner. On a 

 closer examination, however, the metasome is found to be somewhat more slen- 

 der, and the terminal piece of a rather different form. In a less advanced 

 stage, the difference between the two species is much more marked, the meta- 

 some in the present species being almost twice as long as in the corresponding 

 stage of A. paquri, and also much narrower. Its terminal piece, moreover, is 

 not, as in that species, club-shaped, but narrow cylindric in form. The male, on 

 the other hand, is comparatively less slender than that of the type^species, and 

 has the metasome somewhat differently shaped. 



Occurrence. — Of this form I have myself only found 2 specimens with 



