370 MRS. E. w. SEXTO^^ on a [Apr. 28, 



3. On the Amphipod Genus Trischizostonia. 

 By E. W. Sexton. 



[Received March 14, 1908.] 

 (Plates XIV.- XXI.*) 



During the cruise of the ' Huxley ' in the Bay of Biscay, 

 August 1906, a small collection of Amphipoda was taken, which 

 was handed to me by Dr. Allen for examination. 



Amongst them was a large female specimen of Trischizostoma 

 nicceense. On looking into the literature of the group there 

 appeared to be so much confusion with legard to the two genera 

 Guerina and Trischizostoma, that a thorough revision has been 

 necessary. 



To those who so kindly assisted me in this, my best thanks 

 are due : to Prof. G. 0. Sars for his gift of a co-type of T. raschii; 

 to Dott. A. Delia Yalle for sending me his series of pi-eparations 

 of Guerina nicceensis ; to the Rev. T. E. R. Stebbing for permitting 

 me to see his (as yet unpublished) manuscript on the S. African 

 Lysianassidfe, containing the description of a new species of 

 Trischizostoma "f ; to Mons. E. Chevreux for his information con- 

 cerning his specimen of Guer'mella nicceensis ; to Dott. A. Brian 

 for his paper on a specimen from the Gulf of Genoa ; to Mr. W. 

 M. Tattersall for his kindness in forwarding all his specimens 

 to me as soon as he heard I was engaged on this paper ; and to 

 Dr. Caiman for much assistance and for i-evising the manuscript. 



I. Historical. 



The first specimens of this genus were taken at ISTice by the 

 Rev. F. W. Hope and sent by him to the Director of the Naples 

 Museum, Dott. Achille Costa, to be described and added to the list 

 of Crustacea then being prepared for publication in the ' Fauna 

 del Regno di ISTapoli ' (2). 



The description was written by Costa in 1853, a new genus 

 Guei'inia, Hope, being formed, and the type species, Guerinia 

 nicceensis figured, and was published at once with an account 

 of two other crustaceans, under the title of " Tre nuovi 

 Orostacei discoperti dal Rev. Gugl. F. Hope " (1). The description 

 was published again, later in the same year, in the ' Fauna,' but 

 the plate, although alluded to as plate vii. in the text, was 

 omitted. 



Costa recorded the specimens as parasitic on various fish, " sopra 

 uno squalo e sul merluzzo ordinario," to which they were clinging 



* For explanation of the Plates, see p. 400. 



f Since this paper was sent to press, Mr. Stebbing's article, cited below (20), 

 containing the description of this new species, Trischizostoma remipes, has been 

 published" in the 'Annals of the South African Museum,' vol. vi. pt. 1: South 

 African Crustacea, pt.4, by the Rev. T. R. R. Stebbing, M.A., F.R.S., F.L.S., F.Z.S. 

 With 14 plates. Cape Town : April 2, 1908. Pp. 59-64, pi. xxxiv. 



