REPORT ON THE AMPHIPODA. 747 



Family Stenothoid^, G. 0. Sars, 1882. 



Boeck in 1876 coustituted the Stenothoinse the third subfamily of the Leucothoidse, 

 assigning to it the genera Stenothoe, Metopa, Cressa, and by implication Danaia, if that 

 should prove to be distinct from Cressa} In 1882 Sars changed the subfamily into a 

 family. Boeck defined the subfamily as follows : — 



" Upioer Lip apically cleft. 



" Mandibles elongate, apically broad, dentate, not uniform ; the left mandible with 

 an accessory plate ; the molar tubercle minute or absent ; the palp absent, or long, three- 

 jointed. 



" Lower Lip little. 



" First MaxillsB with the palp one- or two- jointed ; the inner plate small or 

 wanting. 



" Maxillipeds with long palps ; the inner plate very small, the outer almost 

 obsolete. 



"The body compressed, but yet thick; the first side-plate little, covered; the 

 rest of the side-plates much increasing in size ; the fourth generally very large, shield- 

 shaped. 



" Antennse moderately elongate ; the upper devoid of accessory flagellum. 



" First Gnathopods slender ; hand often not subchelate. 



" Second Gnathopods with the hand strongly subchelate. 



" Tliird, Fourth, and Fifth Perasopods of the same shape ; first joint of the Third 

 and Fourth generally not dilated. 



" Last Uropods uniramous ; the ramus two-jointed ; the last joint stiliform. 



" Telson small, not cleft." 



Remark. — A rudimentary accessory flagellum is sometimes present on the upper 

 antennse. The right mandible, at any rate in some species, has a secondary plate, though 

 it is less conspicuous than that on the left mandible. 



1 Spence Bate says that the maudihles in Danaia are without a palpiform appendage (Brit. Mus. Cat. Amph. Crust., 

 p. 59 ; Brit. Sess. Crust., p. 67); the genus Cressa of Boeck is distinguislied from Danaia solely by its possession of a 

 three-jointed mandibular palp ; it is therefore worth while to notice that in Spence Bate's British Museum Catalogue, on 

 pi. X., there is a figure of a mandible with a three-jointed palp in close proximity to the figure of Danaia dubia ; 

 unfortunately the mandible is by some accident unnumbered, but the figure .shows it to be of such a character that, 

 unless it belongs to Danaia, it cannot belong to any of the species figured on pi. x. It becomes therefore highly 

 probable that the definition of Danaia requires amendment, and that Cressa of Boeck is a synonym of it, as already on. 

 other grounds it has been con.sidered by Sars. 



