332 CAHL BUVALLIUS, AMPlilPOUA IIYPEUIIDEA. I. 2. PHKONIMID^. 



Genus 1. DAIRELLA, C. BOVALLIUS, 1887. 



Diagn. Caput mugnuin, plus minusve globosum. Peraion latum, post non angustatum. Fedes -perwi 

 priini et secimdi parium siniplices, non subcheliformes, sequentibus simillinii ac paullulo 

 solum breviores. Pedunculus pedum itri ultimi paris valde dilatatus. 



The head is large, and more or less globular. The perceon is broad, not narrowed behind. 

 The first and second pairs of perwopoda are simple, not subchelifonn^ very similar to the 

 following, and only a little shorter. The peduncle of the last pair of uropoda is much 

 dilated. 



Syn. 1887. Dairella, C. BOVALLIUS. — "Systeraatical list of the Aniphipoda Hyperii- 



dea». Bih. t. K. Sv. Vet. Ak. Haiidl. 

 Bd. 11. N:o 16, p. 24. 

 » » Til. Stebbing. IfiSS. »lleport on the Am]3hipoda». Voy. ofH.M. S. 



Challeuger. Zoology. Vol. 29, p. 1342. 



The genus Dairella is one of the niost remarkable among the Hyperiidean genera 

 because it is »isopodous», i. e., all the pairs of pera;opoda are subsimilar in shape, none 

 of thera forming a prehensile organ of any kind. 



The type for the genus was Farajihronima californica, proposed by me in 1885;') 

 at the same tirae as the new genus Dairella was instituted I gave a short description 

 of a new species from the Atlantic, Dairella latissima. 



Stkbbing in 1888 proposed the new specific name Dairella Bovallii for a species 

 which however is no doubt identical with D. latissima. He says that D. Bovallii 

 is distinguished from D. latissima «by the Avrist of the first gnathopods not being twice 

 as long as the hand, and by having the peduncles of the fir.st pair of uropods much longer, 

 instead of shorter, than those of the second pair». The first difference is due to a mis- 

 understandiiig of the wording in my diagnosis, caused by the omission of two comraas; 

 the passage runs, »Carpus of first pair of pereiopoda twice broader and longer than 

 metacarpus», instead of »Carpus of first pair of pereiopoda twice broader, and longer, 

 than metacarpus». The other difference exists but is onlj' sexual, so that in the male 

 specimens the peduncle of the first pair of uropoda reaches fully to the apex of the ped- 

 uncle of the second pair, but in the females it does not reach as far down. At the time 

 when I wrote the original diagnosis I did not knoAv any male specimens. 



The characteristics used for the specific distinction are: 



1. The size of the head. 



2. The length of the fifth pair of perajopoda. 



3. The relation between the length of the femur and of the carpus in the fifth pair. 



4. The breadth of the femur in the last three paii"s of perajopoda, 



5. The form of the rami in the last pair of uropoda. 



') C. BovALLlus. »On some forgotten genera araong the Amphipodous Crustacea». Bih. t. K. Sv. Vet. 

 Ak. Handl. Bd. 10. N:o 14, p. 11. 



