44 ME. A. O. WALKER ON AMPHIPODA 



Genus OKCHOMEisroPSTS, G. O. Sars, 1895. 

 Except as to the telson. 



O. NODiMAisrFS *, n. sp. (PI. 7. figs. 13-17.) 



Cape Adare, Nov. 4 & 5. 26 fath. Many specimens. 



Body slightly compressed ; segments of the mesosomesubequal. 

 Pirst 4 side-plates about twice as deep as the segments, expanded 

 downwards, the 1st produced in front beyond the head, finely 

 granulate and pitted. Metasome with a dorsal carina on the 

 posterior half of each segment : hind and lower margins of the 

 3rd segment almost straight, the former smooth ; posterior 

 angle obtuse but well defined. 



Urosome hardly so long as the last segment of the metasome ; 

 1st segment carinate, 2nd very short. 



Head almost concealed by the 1st segment and side-plate, 

 lateral angle prominent, rounded. Eyes large, dark, reniforni, 

 expanded below. 



Upper antennae : peduncle reaching to the end of the penulti- 

 mate (2nd) joint of the peduncle of the lower antennse, 1st joint 

 more t]ian twice as long as the next two ; flagellum 16-jointed, 

 rather longer than the peduncle, the ]st joint about as long as 

 the next seven : the accessory appendage 7-jointed, the 1st as 

 long as the next three. 



Lower antennae : the last three joints of the peduncle sub- 

 equal, reaching the middle of the flagellum of the uppei 

 antennae. 



Maxillipedes : outer plate with two curved spines on the outer 

 side of the tip ; inner plate with three blunt spines at the 

 tip. 



Eirst gnathopods very robust, the 1st joint expanded distally 

 and posteriorly, the 2nd also much stouter and longer than the 

 3rd and 4th, concave above, convex and setose beneath ; carpus 

 Yery short and produced behind to an irregular conical projection. 

 Propodos narrowing distally, the hind margin about two-thirds 

 the length of the front, concave, setose, ivith a nodiform 

 tubercle about tlie middle ; the palm rectangular, with a cleft in 

 the middle ; the dactylus projecting beyond the palm. 



Second gnathopods normal. 



Peraeopods : 1st and 2nd robust, 3rd joint broad with parallel 



* From nodus, a knot, in allusion to the tubercle on the propodos of the 

 first gnathopods. 



