2G 



SCHIZOPODA. 



Fam. 5. M Y s i D JE. 



HEMIMYSIS LAMORN^E (Couch). 



Cornwall (Couch, the type specimen). Plymouth and 

 Falmouth (A M. N.). 



MESOPODOPSIS SLABBEEI (P. J. van Beneden). 



Falmouth (6r. C. Bourne) ; Whitsand Bay, Plymouth, 

 1903 (_A. M. JV.) ; River Tamar above Saltash, fine and 

 abundant (Biol. Lab.). 



MACROMYSIS FLEXUOSA, Muller. 



Very common in the Laminarian Zone. 



A most valuable and deeply interesting paper upon the 

 coloration and chromatophores of Crustacea, and especially 

 of the Mysidea, has recently been published by Messrs. Keeble 

 and Gamble, " The Colour- Physiolo cry of Higher Crustacea," 

 Phil. Trans. Roy. Soc. ser. B, vol. cxcvi. 1904, pp. 295-388. 



The Rev. T. R. R, Stebbing, in his 'History of the 

 Crustacea,' has written : " Macromysis must yield to the 

 rather queer but much earlier name Praunus, Leach, 1813, 

 of which the unabashed author himself remarks that ' this 

 genus was instituted by Leach, who has derived the name from 

 the English word Prawn'." Leach assigned two species 

 to the genus P. flexuosus, Muller, and P. integer, Leach, 

 and instituted the genus because he thought that it was 

 different from Mi/sis, Latreille. He immediately afterwards 

 recognized his mistake, and in all his subsequent writings 

 he uses Latreille's genus Mysis with his own Praunus as a 

 synonym. There is no character given for his genus Prannus 

 which would distinguish it from My sis, it was an absolute 

 synonym. It would be laughable, indeed, if in the year 1904 

 we had to call a Mysidean a Prawn ! Luckily, there is not 

 an iota of ground for such a calamity. 



MACROMYSIS NEGLECTA (G. 0. Sars). 



1900. Macromysis neglecta, Holt & Beaumont, /. c. p. 19. 



1904. Macromysis nigra, Keeble & Gamble, " Colour-Physiology of 

 Higher Crustacea," Phil. Trans. Roy. Soc. ser. B, vol. cxcvi., 

 especially pp. 331, 332, and 354, pis. xviii., xix., xxi. figs. 10, 

 11, 17. 



We do not understand the grounds on which the name 

 M. nigra is proposed to be substituted for that of M. neglecta. 

 The difference in the chromatophore-system in M. Jiexuosa 

 and M. neglecta is as follows : " Each breeds true. Each 

 possesses before birth its own system of centres and branches 



