KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND. 21. N:0 5. 



17 



The body is depressed not carinated. The head is twice as deep as long, flattened above, 

 with a small rounded projection on each side. The first pair of antenna? are shorter than 

 half the length of the body. The first two pairs of pereiopoda with elongated carpi. The 

 fifth pair are much longer than the sixth; the femur is strongly serrated along the anterior 

 and posterior margins, much shorter than the three following joints together; the spine-like 

 apical process is curved, much longer than the genu; the tibia is a little shorter than the 

 carpus; the carpus is only a little longer than the metacarpus. The seventh pair are shorter 

 than a third of the fifth pair. The last two ural segments are coalesced. The uropoda are 

 very broad, finely serrated; the interior margins of the first pair are spiniferous. The exterior 

 rami of all the pairs are very minute, the interior rami are longer than the peduncles. The 

 first pair of uropoda are longer than the following. The telson is very small, triangular, pointed. 



Colour. Hyaline. 



Length. 5,5 mm. 



Hab. The Lofoten Islands, west coast of Norway. 



Tyro borealis, G. O. Sars. 

 Facsimile from G. O. Sars. Overs, of Norges Crust., pi. 3, fig. 1. 



Syn. 1882. Clydonia borealis, G. 0. SAES. 



Tyro 



C. Bovallius. 1887. 



»Oversigt af Norges Crustac6er», etc. 



Christiania Vidensk. Selsk. Forhandl. 



1882. N:o 18, p. 77; pi. 3, fig. 1, 



1 a and 1 b. 

 » Arctic and Antarctic Hyperids». Vega- 



Exp. Vetensk. Iakttagelser. Bd. 4, 



p. 551. 



This species seems to be intermediate between Tyro Sarsi and Tyro Clausi but is 

 easily distinguished from the first by the short antennae, by the strongly serrated anterior 

 margin of the fifth pair of pereiopoda, and by the spiniferous interior margin of the 

 first pair of uropoda. From Tyro Clausi it differs by the length of the fifth pair of 

 pereiopoda and of the first pair of uropoda, and by the minute exterior ramus of the last 

 pair of uropoda. 



The body has a very thin tegument. 



K. Vet. Akacl. Handl. Band. 21. N:o 5. 



