278 CAEL BOVALLIUS, AMPHIPODA HYPERIIDEA. I. 2. HYPERIID^. 



Euthemisto. 



In 1830 H. MiLNE Edwards gave a somewhat improved diagnosis. It runs: 



»Tete grosse et renflée; antennas simples; thorax divisé en sept segmens, dont le premier 

 et bien distinct; pattes de la seconde paire terminées par une petite main imparfaitement di- 

 dactyle.» 



In the same yeai' Latreille gave a generic description, taken probably from that 

 of GuÉRiN, but more adequate in form. I quote the following passage: 



» — — — — quatorze pieds, les quatre antérieures beaucoup plus petits que les suivans, 

 les seconds terminés par une pince didactyle, ceux de la cinquiéme paire beaucoup plus longs que 

 les autres, avec le quatriéme artide armé en dedans d'un rang de petites dents en forme de 

 peigne.» 



In 1838 H. MiLNE Edwards gave a short description of the genus, which description 

 is important because here for the first time it is pointed out that the form of the carpus 

 of the third and fourth pairs of perajopoda is a characteristic for this genus. I quote 

 only the passage in question: 



» — — — — mais les pattes de la troisiéme et quatriéme paires, au lieu d'étre gréles et 

 cylindriques, portent une espece de main triangulaire formée par rantépénultiéme article, sur le 

 bord duquel s'infléchit une gi'iffe formée par les deux derniers artides.» 



In 1839 Lucas repeated the description given by Latreille. 



In 1840 H. MiLNE Edwards gave a good description, from which the following 

 may be cited: 



»Les patés de la premiére paire sont complétement dépourvues de main chéliforme; 



— — Enfin les fausses patés qui gai'nissent rextrémitc de rabdomen sont plus longues et plus 

 gréles que chez les Hypéries, mais présentent, du reste, la méme disposition.» 



It may be noticed that he expressly points out the close relationship between Hy- 

 peria and Themisto. 



In 1852 Dana placed the genus Themisto in the second subfamily, Phrosinmce, of 

 his second Hyperiidean family, Phronimidce, thus removing it from its due place next to 

 Hyperia. He gave the following short diagnosis: 



»Pedes 3tii 4tique prehensiles, manibus latis. Manus pedis 5ti elongate lineares, digito 

 recto, longissimo, tenui.» 



In 1862 Spence Bate, reintroducing the genus in the family Hyperidce, gave the 

 following diagnosis: 



»Cephalon transversely ovate. Pereion not largely distended. Pleon slender. Eyes occupy- 

 ing the entire cephalon, dorsally separated. Antennse subequal, as long as the cephalon is 

 deep; superior pair having the flagellum not articulated; inferior pair having the flagellum more 

 or less articulated. Mandible having an appendage. First pair of gnathopoda short, tolerably 

 robust; carpus not having the anterior margin inferiorly produced; second pair having the carpus 

 on the inferior angle anteriorlj' produced. First pair of pereiopoda having the carpus dilated; 

 propodos narrow, and capable of being inflected against the carpus: second pair like the first; 

 third pair twice the length of the second; carpus very long; propodos longer than the carpus, 

 fringed along the anterior margin with a comb-like series of teeth, and capable of impinging 



