394 Mr. A. O. Walker on 



LTV. — Podocerus and Jassa of Leach. 

 By Alfeed 0. Walke'e. 



Me. Stebbing's unrivalled knowledge of the literature of the 

 Amphipoda and the careful accuracy of his work are so well 

 known that a corroboration of the conclusion he arrived at in 

 the paper in the March number of this Journal, viz. that the 

 true Podocerus of Leach is Platophium Darwinii (Bate), is 

 scarcely needed. Nevertheless, as the revolution in nomen- 

 clature caused by this discovery is so serious that persons 

 maybe found who will object that something more is required 

 to support it than Milne-Edwards's admittedly inaccurate 

 description and figures, 1 venture to offer the following- 

 evidence. Having ascertained, by examination of Leach's 

 type specimen last October, that Jassa pelagica, Leach, was 

 not the female of Podocerus falcatus (Mont.), but was (to use 

 G. 0. Sars's name) Janassa capillata (Ratlike), I was led to 

 undertake an examination of the history of the genus Podo- 

 cerusy in which I have always taken a special interest. I was 

 of course not aware that Mr. Stebbing was doing the same. 

 I arrived substantially at the same conclusions as Mr. Steb- 

 bing, but, unlike him, was unable to identify Milne-Edwards's 

 description and figure with any known Amphipod, as I could 

 not suppose him to have invented the dorsal teeth on the 

 three segments. 1 therefore postponed the conclusion of a 

 paper I had written on the subject till I could again examine 

 the type specimens of Podocerus variegatus, Leach, at the 

 British Museum. This was delayed through a visit of six 

 weeks to the south of France, and it was only in passing 

 through London on my way home in the middle of March that 

 I was able to do so with the kind assistance of Mr. R. I. 

 Pocock. Neither he nor I then knew of Mr. Stebbing's paper, 

 so that the opinion we both formed was absolutely unbiassed. 

 The type specimens, of which there are several, are either 

 pierced with a pin or gummed on a piece of card. There are 

 at least two species among them, one being apparently the 

 female or young of P. falcatus (Mont.). The other, however, 

 we had no difficulty in deciding to be the species Milne- 

 Edwards intended to represent minus the dorsal teeth. The 

 antennas, fortunately, are nearly perfect, and though the first 

 gnathopods are either gone or hidden, yet the second gnatho- 

 pods, a first or second pergeopod, and one or two of the last 

 perseopods still remain. Mr. Pocock and I agreed that these 

 corresponded with Platophium ; but having Sars's figure 

 of Lcetmatophilus {Platophium) tuberculatus (Bruz.) before us, 



