KONGL. SV. VET. AKADKMIENS HANDLINGATC. BAND. 22. N:0 7. 265 



Colour. (?)• 



Length. »Six to eight lines» (Dana). 



Hal>. »Probably from Lagulhas Bank, near Cape Horn» (Dana). 



Syn. 1852. Hyperia trigona, J. D. DANA. — United States Exploring Expedition. 



Crustacea. Vol. 2, p. 987, pi. G7, 

 fig. 12. 

 Parathemisto trigona. » C. Bovalmus. 1887. "Systematical list of the Amphipoda 



Hyperiidea». Bih. t. K. Sv. Vet. Ak. 



Handl. Bd. 11. N:o 16, p. 21. 



» » » » 1887. » Arctic and Antarctic Hyperids». Vega- 



Exp. Vetensk. Iakttagelser. Bd. 4, 

 p. 5G8. 



Parathemisto trigona comes near to P. pacijica and P. japonica, and the di- 

 stinctions between the three species are very small, as for instance the want of a terminal 

 spine in the carpal process of the second pair of peraeopoda in Parathemisto trigona 

 and also the comparatively long peduncle of the last pair of uropoda. 



Dana's description follows here: 



»Body very much compressed, the back rising to an edge. Antennae longer than the head; 

 superior pair subulate, inferior long (reaching nearly to fourth thoracic segment), very slender, 

 flagellum indistinctly jointed. Feet very short, setulose; six 1 ) posterior pairs long and subequal, 

 the seventh pair a little the shortest; fourth joint of third or fourth pair rather broad. — — — 

 The thin body, narrow triangular in its section, and sharp-backed, is unlike that of any Hyperia 

 described. About fourteen indistinct joints may be counted in the flagellum of the inferior an- 

 tennae. The first pair of legs terminates in a small claw, and is not at all prehensile; the third 

 joint is rectangular at lower apex. The second pair has a process to lower apex of fourth joint, 

 nearly three-fourths as long as the finger (or fifth joint); along the back of the fifth joint, there 

 are four or five short hairs, or pairs of hairs. The fourth joint of the fourth pair is more than 

 twice the width of the fifth joint; and both joints, besides four to seven short hairs (not longer 

 than diameter of fifth joint), have on the lower side exceedingly minute spinules, closely set, 

 seen only with a high magnifier. The fifth joint of the legs of the fifth pair, has six or seven 

 pairs of short hairs on lower margin, not longer than diameter of joint. The caudal stylets have 

 the lamellae of each unequal, the shorter nearly two-thirds as long as the longer, and both 

 pointed.» 



') A typographical error instead of »three». 



K. Sv. Vet. Akad. Handl. Band. 22. N:o 7. 



34 



