Crustacea. 241 



Thoracic appendages. The first of these in the male reaches an 

 extraordinary development. The dactylus is very long and slender, 

 much curved near its extremity. The propodos is more than half as 

 long, stout, and has articulated to it a piece which is curved through 

 a right angle. This piece bears a tooth at the extremity on the outer 

 margin, and a rounded projection or tubercle on the inner. The 

 carpus is distinctly shorter than the propodos, and is broad, somewhat 

 irregular proximally. The meros is very large and irregular, besides 

 being considerably and irregularly expanded distally. It bears a 

 large lateral wing externally near the proximal end. 



The remainder do not present any striking features. The three 

 anterior pairs are a little longer and more delicate than the 

 posterior three. These latter have one or two truncated spines 

 at the termination of some of the joints. 



Pleopoda. A rounded basipodite, with ovoid exo- and endopodites 

 arising some little distance apart. The exopodite is smallest, and 

 both have long setae on the inner margin. 



Uropoda. The two-jointed exopodite equals in length the first 

 joint of the endopodite. The former terminates in two long setae, the 

 latter possesses four. 



Owing to an accident with the preparations further anatomical 

 details cannot be given. 



Size about 4 mm. 



Eight specimens, four ^ , four ? , were taken off Cape Adare, in 

 20 to 24 fathoms, from the roots of seaweed. Temperature 29° Fahr. 



Gnathia. 



Of this interesting genus a very large number of species, some- 

 thing like twenty-five, are known, nearly all of them coming from 

 European waters. For our knowledge of these species we are mainly 

 indebted to the works of M. Hesse (11 and 12) and Professor G. 0. 

 Sars (29). Mr. Beddard has described four species from the ' Challenger ' 

 collections, and, with the exception of the species described below 

 and another from New Zealand, these are all that are known from 

 extra-European seas. 



Gnathia polakis. 



(PI. XXXII.) 



Specific character. Pointed cephalon, more pronounced in male. 

 Scythe-like character of the mandibles in male, and the markings on 

 the two penultimate segments of the thorax. 



