258 



CARL BOVALLIUS, AMPHIPODA HYPER1IDEA. I. 2. 



HYPERIID^E. 



2. PARATHEMISTO JAPONICA, C BOVALLIUS, 1887 



PI. XII, fig. 17—43. 



Diagn. Corpus carinatum. Caput segmenta duo priora peraei longitudine asquans. Carpus pedum 

 percei prirai paris metacarpum longitudine asquans; margo anterior ac posterior spinis ar- 

 mati; margo posterior metacarpi serratus, spinis carens; dactylus dimidio metacarpi paullo 

 longior. Metacarpus pedum secundi paris carpo brevior; processus carpalis tres partes 

 metacarpi longitudine requans, spinam terminalem brevem gerens; dactylus dimidio meta- 

 carpi brevior. Metacarpus pedum tertii ac quarti parium carpo non longior. Metacarpus 

 pedum parium trium ultimorum articulos duo prascedentes longitudine aaquans. Pedunculus 

 pedum uri ultimi paris quam telson haud ter longior; rami asquales. 



The body is carinated. The head is as long as the first two pergonal segments together. 

 The carpus of the first pair of per wop o da is as long as the metacai-pus; the front and hind 

 margins are provided with bristles; the hind margin of the metacarpus is serrated, and 

 without bristles; the dactylus is a little more than half as long as the metacarpus. The 

 metacarpus of the second pair is shorter than the stem of the carpus; the front side of 

 the carpal process is three-fourths as long as the hind margin of the metacarpus, and has 

 a short terminal spine; the dactylus is not half as long as the metacarpus. The meta- 

 carpus of the third and fourth pairs is not longer than the cai-pus; that of the last three 

 pairs is as long as the two preceding joints together. The peduncle of the last pair of 

 uropoda is not fully three times as long as the telson; the rami of the last pair are equal 

 in length. 



Colour. Yellowish red. 



Length. 10 — 16 mm. 



Hab. The Northern temperate and subtropical region of the Pacific. (D. M.; F. M.; S. M.) 



Syil. 1887. Parathemisto japonica, C. BOVALLIUS. "Systematical list of the Amphipoda 



Hyperiidea». Bih. t. K. Sv. Vet. 



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



» » » Th. Stebbing. 1888. "Report on the Araphipoda». Voy. 



of H. M. S. Challenger. Zoology. 

 Vol. 29, p. 1423. 



Parathemisto japonica is a stout and strongly built animal and resembles a 

 Hyperia rather than a Parathemisto in the general form of the body; from Parathe- 

 misto paciftca it is distinguished by the equal rami of the last pair of uropoda and by 

 some other smaller differences. The difference between the genera Parathemisto and 

 Eutkemisto is so small that there is only one characteristic, namely the equality in length 

 of the last three pairs of perasopoda that prevents the present species of being included 

 in the genus Eutkemisto. On the other hand the development of the carpus of the fifth 

 pair is stronger than in any other species of Parathemisto; but this is compensated 

 for by the fact that in the sixth and seventh pairs also of Parathemisto japonica the 

 carpus is developed in almost the same degree. 



