GNATHIIDJE. 37 



perfectly smooth. The metasome is rather short, and usually 

 carried bent under the last segment of the mesosome ; the 

 pleopods (fig. 7) are quite devoid of all swimming-setae. 

 The upper antennas (fig. 1) have the five-jointed flagellum 

 shorter than the last joint of the peduncle. In the lower 

 antennae, the last two joints of the peduncle widen at their 

 extremities, and the seven-jointed flagellum is shorter than 

 the preceding joint. The mandibles (fig. 2) suddenly swell out 

 on the inner side near the base ; on the outer side is a shoulder 

 and distinct notch, the extremity is bent slightly inwards, the 

 inner margin is crenulated, crenulations 10-12 ; the greatest 

 breadth of the mandible is situated below the notch of the 

 outer margin. The second feet have the propodos bearing 

 two spines, the distal one situated close to the base of the 

 finger ; the carpus and wrist bear two or three nodules. 

 The sides of the telson (fig. (i) gradually converge to the 

 extremity. 



The female is accurately represented by Bate and Westwood 

 (vol. ii. p. 192) ; the five segments of the mesosome are all 

 distinct ; the head is much wider than long, the front margin 

 broad and straight (fig. 8) ; the total length of the body is 

 not more than double that of the unusual breadth. 



Length of male 5 mm., breadth 1*75 mm. 



This is a common species on the coasts of Devon and 

 Cornwall, and must clearly have been the species which 

 Montagu found and described as Cancer maxillaris. 



GNATHIA OXYURJSA (Lilljeborg). (PI. II. figs. 9, 10 j 

 PI. III. figs. 1-5). 



1855. Anceus oxyunpus, Lilljeborg, " Om Ilafs Crustaceer vid 

 Kullaberg i Skane,'' (Efvers. K. Vet.-Akad. Forhandl. 1855, 

 p. 133, J. 



1855. Praniza cceruleata, id. ibid. p. 132, $. 



1866. Anceus Edwardii, Bate & Westwood, vol. ii. p. 201, 9. 



1897. Gnathia maxillaris, G. O. Sars, Crust. Norway, vol. ii. Isopoda, 

 p. 52, pis. xxi., xxii. fig. 1. 



This is the Gnathia which Sars in his earlier papers called 

 Anceus oxyurceus, Lilljeborg. 



Front margin of cephalosome with three nodular pro- 

 jections, the central larger than the lateral, rounded distally 

 (not flattened as in the last species) ; hinder segments of 

 mesosome with smooth surface; metasome fully equal in 

 length to last two segments of mesosome, carried outstretched; 

 telson w r ith sides gradually and evenly converging to the end. 

 Mandible sublanceolate (fig. 9), broadest in the middle, where 

 on the inner side the rounded sweep is at its maximum, beyond 



