232 EEV. T. E. E. STEBBING ON THE 



Fam. Gnathiid^. 

 1814. Gnathides Leach, Edinb. Encycl. vol. vii. p. 432. 



1880. Gnnthiidce Harger, U.S. Comm. Fish and Fisheries for 1878, part vi. pp. 304, 308. 

 1900. Gnathiidce Stabbing, in Willey's Zoological Results, part v. p. 625 (with synonymy). 

 1906. Gnathiidce Norman and Scott, Crustacea of Devon and Corn-wall, p. 36. 

 1911. Gnathiidce Tattersall, Nordisches Plankton, vol. iii. part vi. p. 192. 



Gen. Gnathia Leach. 



1813. Gnathia Leach, Edinb. Encycl. vol. vii. p. 402. 



1835. Gnathia Westwood, Loudon's Magazine of Natural History, vol. viii. p. 273. 



1880. Gnathia Harger, U.S. Comm. Fish and Fisheries for 1878, part vi. p. 410. 



1900. Gnathia Stebbing, in Willey's Zoological Results, part v. p. 625 (with synonymy) . 



1905. Gnathia Harriet Richardson, Bull. U.S. Nat. Mus. no. liv. p. 56. 



Gnathia ceistatipes. (PL XXTV. A.) 

 Stebbing, Abstract P.Z.S. 1912, p. 42 (Nov. 5th). 



The length of the specimen exceeded three times the greatest breadth by the length 

 of the telsonic segment. The head has a circular appearance, being slightly broader 

 than the median length including the coalesced first segment of the peraeon ; the front 

 is a little emarginate, then sloping on each side to a small outward-turned projection. 

 The second, third, and fourth segments of the peraeon are quite distinct, with dorsal 

 impressions which in the fourth give the back a corrugated look. The large fifth and 

 sixth segments are scarcely distinguishable except laterally, and each has two lateral 

 incisions queerly suggestive of extra segmentation which is not to be thought of, while 

 ventrally the markings imply complete coalescence of the two segments. The limbless 

 seventh segment is as usual very small. The pleon is shorter than the breadth of the 

 peraeon, somewhat tapering, with the lateral angles acute, pointing backwards. The 

 telsonic segment is at the base broader ttian the length, the tapering division scarcely 

 longer than the basal, the small truncate apex carrying a pair of setules. 



No eyes were perceived. 



The first antennse have the first joint much broader but little longer than the third, 

 which is longer than the second; the slender fiagellum has five or six joints. The 

 second antennae have the last joint of the peduncle rather longer than the penultimate, 

 the three preceding joints short, the middle one a little the longest; the slender 

 eight-jointed flag«llum is not quite so long as the last two joints of the peduncle 

 combined. 



The mandibles have the look of being two-jointed, the second joint forming a 

 somewhat triangular blade with the distal extremity pointing inwards with a slight 

 curvature. 



The maxillipeds have the large second joint produced into a very distinct plate, 



