446 Mr. G. M. Thomson on two neio 



Dorsum witli three rows of tubercles, the posterior two rows 

 very faint. Keels with L'\teral margins entire, though 

 granular, those that l)ear the pore notched or eraarginate 

 posteriorly. Pores completely marginal, though just visible 

 when the segment is viewed from above. 



Caudal process semicircularly rounded. 



Anal sternite bitubercular. 



Sterna not spined. 



Polydesrnorhachis atrafus, sp. n. 



$ . — Colour of upper sui'face a uniform blackish brown, 

 the edges of the keels only indistinctly yellow ; legs and 

 antennffi infuscate ; sterna pale. 



Antennae short, their length a little less than width of 

 second segment. 



First tergite mesially depressed, elevated laterally and 

 posteriorly, beset with tubercles and granules. Keels of 

 segments 2 to 7 elevated, the rest horizontal ; anterior and 

 posterior borders of keels as far back as the seventeenth 

 segment directed obliquely forwards, almost smooth, anterior 

 border basally shouldered, anterior angle rounded and nearly 

 rectangular, strongly convex on the sixteenth, seventeenth, 

 and eighteenth segments; anterior border straight on the 

 anterior part of the body, convex on the posterior seven keel- 

 bearing segments ; posterior angle never spiniform, obtusely 

 rounded, square on the sixteentli, produced on the seventeenth 

 to nineteenth. The dorsal surface of keels and of the rest of 

 the segment granular, in addition to the tubercles ; the suture 

 of the segments costulate. 



Measurements in millimetres. — Total length 61 ; width of 

 second segment 8'5, of fifth 8"5. 



Loc. Palawan Island, between Borneo and the Pliilippines 

 {A . Everett) . 



LII. — On tu:o neiv Gammar ids from New Zealand. 

 By George M. Thomson, F.L.S. 



[Plate X.] 



The Amphipods described in the present paper were 

 obtained in the Bay of Islands in January 1884. They were 

 taken by me in the dredge in about 8 fathoms of water on a 

 nearly clean sandy bottom. Only males were met with, and 

 as, in the case of both species, they were very distinct and 

 conspicuous on account of the abnormal development of the 



