1062 THE VOYAGE OF H.M.S. CHALLENGER. 



the Microcleutopinse. To the Leptocheirinse he assigns the genera Leptocheirus and 

 Goesia ; to the Photinae Photis, Microprotopus, and Xenoclea ; to the Microdeutopinae 

 Microdeutopus, Aora, Autonoe, Protomedeia, Gammaropsis, Podoceropsis, and Megam- 

 phopus. In 1882 Sars made of the Microdeutopinae the family Microdeutopidse, 

 including in it the genera just named, except that he does not specify Megamphopus ; 

 at the same time he united the Leptocheirinse and Photinse to form the family Photidse, 

 placing in it the genera Ptilocheirus [Leptocheirus], Photis, Microprotopus, and 

 Xenoclea, presumably only omitting Goesia as not belonging to the fauna with which 

 he was then concerned. By Gerstaecker, in 1886, all these genera except Photis 1 are 

 placed in "' Tribus I. Corophiina (Marcheurs, M.-Edw.)," " Fam. 3. Corophiidse 

 Dana," " 2. Gruppe," while Photis is placed in " Tribus II. Gammarina genuina 

 (Sauteurs, M.-Edw.)," "Fam. 6. Gammaridae," " Subfam. 5. Gammarina" 



Boeck defined the family Photidse as follows : — 



" Upper Lip broad, apically rounded. 



" Mandibles strong, apically dentate ; the secondary plate also dentate ; the molar 

 tubercle prominent ; the palp three-jointed. 



" First Maxillse with the inner plate generally small or of moderate size. 



" Second Maxillse with the plates broad. 



" Maxillipeds generally furnished on the inner margin [of the outer plates] with 

 teeth, few, but strong, as they approach the apex longer and curved, sometimes 

 furnished with slender spines ; the last joint of the jmlp rarely not unguifurm. 



" The body more or less compressed, with the back rounded. 



" Upper Antennae with the accessory flagellum small or absent. 



" First Gnatliopods with a subcheliform hand. 



" Second Gnatliopods with the hand subcheliform, seldom scarcely subcheliform. 



" The Fourth Perseopods as a rule much longer than the Third, and the Fifth than 

 the Fourth. 



" The Third Uropods birarnous, rarely uniramous. 



" Telson thick." 



The distinctions which Boeck seeks to establish between the three groups which he 

 calls subfamilies of this family are not very easy to appreciate. Indeed in my opinion 

 Xenoclea, Boeck, the third genus of the Photinge, is identical with Podoceropsis, 

 Boeck, the sixth genus of the Microdeutopinae. In Photis the inner ramus of the 

 third uropods is minute, and in Microprotopus these uropods have but one ramus, so 

 that there might be some reason for placing these two genera in a separate group, but 

 if the Leptocheirinae and Photinse are combined, it seems impossible to formulate a 

 definition that will separate them from the Microdeutopinse. Boeck's Leptocheirinaa 



1 He does not name Norman's Megamphopus, which is only incidentally mentioned by Boeck, and has probably 

 often escaped notice from the fact that the description has only been published in the British Association Reports. 



