ISOPOD GENUS LIGIA. 691 



• 1. LiQiA OCEANICA (Linnteus). 



Ligijda oceanica Richardson (1905), p. 684 [q. v. for complete 

 synonymy). 



Ligia oceanica Dahl (1916), p. 32. 



Male specimen described. 



Length 25 mm. Breadth 12 mm. 



Surface moderately coarsely gi'aniilated. Eyeso^ moderate size, 

 rounded and separated by twice their horizontal length. Antenncp 

 moderately long and stout ; flagellum reaching as far as the hind 

 border of the 4th thoracic somite, the peduncle half-way down 

 the 2nd somite. Flagellum with 12 to 14 very short and stout 

 segments. Coxal plates divided by veiy distinct grooves from 

 terga of every thoracic somite in both sexes. Abdomen not 

 abruptly contracted. Telson arcuate ; the postero-lateral processes 

 acute and nearly as long as the, middle of the hind border; 

 accessory processes not produced, but the inner forming a 

 prominent undulation. Mouth-jyarts : 2nd maxilla bilobed, with 

 two hairy bristles on inner side. Maxillipede palp clearl}^ divided 

 into five joints. 1st ^Jerceojjod of the male only has merus, carpus, 

 and propodus produced on inner side to a flat plate-like expansion, 

 with free border fringed with short setfe. The surface of this 

 expansion is covered by oblique serrations. U^rojjods 7 mm. 



Distribution. Hammershus ; Cuxhaven ; Portsmouth ; Northern 

 Seas. (See Richardson (1905) for complete list.) 



Figured in full by Sars (1899). 



2. Ligia pallasii Brandt. (PI. I. fig. 4.) 



Ligijda jMllasii Richardson (1905), p. 682 (q. v. for synonymy). 

 Ligt/da jKcUasii Richardson (1909), p. 125. 



Male specimen described. 



Length 35 mm. Breadth 20 mm. 



S'urface coarsely granulated. Eyes of moderate size, rounded 

 and separated by twice their horizontal length. Antennce 

 moderately long and stout ; flagellum reaching as far back as hind 

 border of 5th somite, peduncle to hind border of 2nd somite ; 

 flagellum with 15 short and stout segments, without large setse 

 but densely covered with exceedingly minute setae, Coxal plates 

 divided by deep and distinct grooves on every thoracic somite in 

 both sexes. Abdomen not abruptly contracted, with prominent 

 oblique carinoe on each side of 3rd, 4th, and 5th somites. Telson 

 arcuate ; postero-lateral processes acute, produced as far as or 

 beyond middle of hind border ; accessory processes not produced, 

 but the inner forms a prominent undulation. Telson twice as 

 broad as long. Mouth-parts as in L. oceanica. 1st, 2nd, a,nd 3rd 

 perceopods with carpus and merus expanded as in oceanica. 2nd 

 and 3rd legs with small process on pi-opodus not reaching beyond 

 the dactyl in both sexes. Uropods 8 mm. 



Proc. Zool. Soc— 1922, No. XLVII. 47 



