Mr. A. O. Walker — Notes on Amphipoda. 31 



has a yellow mark in front ; the anterior and middle tibia? 

 are yellow in front, and the hind tibia is yellow at base. A 

 female amiculiformis is from flowers of Eucalyptus . 



Prosopis constricta, Ckll. 



Maekay, May 1899, at flowers of Xantkorrhoea (Turner). 



P. subplebeia, Ckll., and P. coronata, Ckll., were taken by 

 Turner at Maekay, November 1891. A small example of 

 P. constricta (Maekay, Nov. 1891) has clear ferruginous 

 tegula?, but it is evidently only a variety. 



III. — Notes on Amphipoda. 

 By Alfred 0. Walker, F.L.S., F.Z.S. 



Stenothoe validus, Dana. 



In 1853 Dana described the above species from Rio Janeiro 

 as having the second joint of the third perajopods expanded 

 like that of the fourth and fifth pairs, instead of linear as in 

 the first and second. Since that time about twenty other 

 species have been added to the genus, but without an excep- 

 tion, so far as is known, these have the second joint of the 

 third per&opods narrow or linear. In the Amphipoda 

 Gammaridea of ( Das Tierreich ' this feature forms one of the 

 characters of the genus, an exception being made in favour of 

 S. validus. The question therefore arises, Did Dana make a 

 mistake in stating that the joint in question was similar to 

 that of the next two pairs? It should be borne in mind that 

 this joint can only be seen by removing the large side-plate 

 of the fourth segment, and that dissection was not so common 

 ) in those days as now ; that the genus was new ; and that the 

 probability, judging from the structure of the majority of 

 species of Amphipoda, was that the third pergeopods should 

 resemble the fourth pair rather than the second. 



The possibility of such a mistake having been made by 

 Dana is shown by the errors of other systematists in describing 

 this or allied species of Stenothoe. Thus : — 



(1) Spence Bate (Cat. Amph. Brit. Mus. p. 60), having 

 copied Dana's definition of the genus, which says that " The 

 basos of the antepenultimate pair of pereiopoda is squami- 

 formly developed," includes S. clypeata, Stimpson (Mar. 

 Invert. Grand Manan, p. 51), and figures the third peraeopoH 



