570 Trof. C. Chilton on a 



1. Tliat the females of the known species as mentioned in 

 Prof. Chilton's article cannot be ilitFereiitiatcd. 



2. That S. Saundersii, Stebbing, may be the female of 

 S. typi'ca (Chilton), S. annata (Chevreux), of the ' Discovery ' 

 species, or of a male, not yet discovered, distinct from all three, 

 i\\\<\ that, consequently, we are not justified in referring any 

 of them to it. 



1'he ' Discovery ' species, which I propose to call Seha 

 antarctica, appears to offer an exanij)le of male dimorphism. 

 The commonest form resembles the female so closely in size 

 (4'25 mm.) and structure that they can only be distinguished 

 by the absence of the incubatory lamella?. But in one 

 gathering two males, measuring respectively 5 mm. and 7 mm., 

 occurred, remarkable for the great expansion of the meral 

 joints of the last three pairs of pera^opods, especially in the 

 larg( r specimen. The hand of the first gnathopods is more 

 ])crfectly chelate than in either S. typica or S. armata. 



It is a question whether any of the above species ought to 

 have been placed in the genus Seha ! In the ' Catalogue of 

 Aniphipodous Crustacea (Brit. J\Ius.)/ p. 159, pi. xxix. 

 fig. 5, tSp. Bate defines iSeba, which he attributes to A. Costa, 

 as having long antennae, sinall coxa?, and uniform, snhequal, 

 and chelate gnathopoda. None of the characters italicized fits 

 the above three species, nor can the hand of the first gnathopods 

 of the male S. typica, as figured by Prof. Chilton, be properly 

 called chelate. To complete the confusion, Prof. A. Costa 

 denied having ever established either the genus or species of 

 "/lb', innomiituta, A. Costa, Poeiii Crost. de Messina,'' as 

 given by ISp. Bate, who further says, at the end of his 

 description, that they are ttiken " from a figure given in a 

 memoir in the possession of Prof. l^f.-Edwards, but I have 

 some doubt of the correctness of my notes both as to the 

 title of the work and the specific name " ! * — Alfijed O. 

 "Walkeij.J 



In 1884 t I described under the name Teraticum typicum^ 

 gen. et sp. n., a small Amphijiod taken in Lyttelton Harbour. 

 1 had three sj)ecimens, in two of which the first gnathopod 

 was large and subchelate, while in tlie third specimen it was 

 smaller and chelate. fcJubsequently the Kev. T. B. R. 

 Stebbing called my attention to the resemblance between my 

 species and one described by him under the name Seha 



* ' Challenger ' Eepoit, vol. xxix. p. 334 ; Delia Vallt', ' Fauna Ac. 

 Golf. Neap.,' Liaiumarini, p. 774. 

 t Trans. N. Z. Inst. xvi. p. 'Ibl^ pi, xviii. ligs. 1 «-!/. 



I 



