— 4» - 



processes unusually long and slender, without any expan- 

 ded part. — Length of the largest female 3o mm., of a 

 male 24 mm. 



Bering Sea and North-West Pacific. 



T. spinifera Holmes. — Holmes has published (7) a 

 good description with figure of his single specimen of this 

 fine species. In the female the two distal peduncular joints 

 are much shorter than in the female of T. longipes, and 

 the third joint is somewhat shorter than the second ; in the 

 male these two joints are at least as long as, and slightly 

 thicker than, in the female, and a large upper part of the 

 wall at the end of the inner side of second joint is produ- 

 ced upwards and forwards as an oblique plate, the termi- 

 nal margin of which is rounded, very oblique and furnished 

 with a very close row of fine, rather long and distally 

 curved setae directed upwards and forwards. The copula- 

 tory organs with the processes considerably shorter than 

 in T. longipes, somewhat similar in outline to those of 

 T. inermis. — Length of large female 26 mm., of a 

 male 20 mm. 



California, Alaska. 



T. inermis Kr. (Rhoda or Boreophausia inermis Kr., 

 Thysanoëssa ne glee ta Kr., T. boreal is G. O. S). — It is 

 scarcely necessary to add anything to the detailed account 

 in the second chapter of this well-known species. 



T. longicaudata Kr. (== T. tenera G. O. S.). — This 

 small, slender species differs from T. parva and T . gregaria 

 by having the sixth abdominal segment somewhat longer 

 in proportion to the combined length of the two preceding 

 segments than in the two other species. In cases of doubt 

 the absence of a minute denticle on the lateral margins of 

 the carapace behind the middle is a deciding character. 

 Good figures of the female are given by Holt and Tatter- 

 sall (<?); in this sex the third peduncular joint of the anten- 

 nulae is a little longer and conspicuously thinner than the 

 second, while in the male second joint is slightly shorter 

 and thicker, third conspicuously shorter and thicker than 



(210) 



