CRUSTACEA CASPIA. 307 



27. Corophium mucronatum, G. 0. Sars, u. sp. 



(PI. XXIV, ligs. 1-7). 



Specific Characters. — Frontal edge of cephalon angularly produced in 

 tlie middle, lateral lobes comparatively sliort. Superior antenna' of moderate 

 length, and in both sexes but sparingly setous, 1st joint of tlie peduncle ex- 

 ceeding the other 2 combined, and having below 3 distant spiuules, Hagellum 

 equalling in length tlie peduncle. Inferior autenuiw in male rather strong, 

 with the penultimate joint considerably tumefied, subfusiform, and produced 

 at the end posteriorly to a long mucroiiiform projection reaching beyond the 

 midle of the last joint, aiid having at the base a small secondary tooth, last 

 Joint somewhat sliorter tiiau the penultimate one, and provided near the 

 base posteriorly with a short recurved prominence, but witliout any spiui- 

 form process at the end. Anterior pairs of pereiopoda moderately strong, 

 meral joint rather much expanded distally, and clothed anteriorly with 

 slender bristles. Last pair of pereiopoda with the outer joints unusually 

 broad, sublaminar. Uropoda and telson of the usual structure. Lengtli of 

 adult male 6 mm. 



Eemarks. — At first sight tlie present species somewhat resembles 

 G. chelicorne, but is, on closer examination, easily distiuguislied by the 

 very slender mucroniform projection of the penultimate peduncular joint of 

 the inferior anteumo, and by the want of a spiuiform process at the end of 

 the last peduncular joint. Moreover, this species is very prominently dis- 

 tiuguislied by the structure of the last pair of pereiopoda, the outer joints 

 of which exhibit a quite uuusual broad, sublamellar shape. 



Description of the adult male. — The length of the body in an apparently 

 full-grown specimen scarcely attains 6 mm., and this form is accordingly 

 somewhat inferior in size to the preceding ones. 



The form of the body (see fig. 1) is that cliaracteristic of the genus, 

 being on the Avhole not very slender. 



The cephalon has the frontal edge (see tig. 2) considerabl\ produced be- 

 tween the bases of the superior antenus, forming in the middle an acute 

 angle. The lateral lobes are comparatively short and narrowly rounded at 

 the tip. 



The coxal and epimeral plates exhibit the usual appearance. 



The urosome (tig. 7), as in the 3 preceding species, has the line of de- 

 marcation between the last 2 segments less distinct than that between the 

 1st and 2nd. 



The eyes are small, rounded, with dark pigment. 



'tH3.-MaT. CTp. 215. 33 



