26 THE ZOOLOGIST. 



mud for breathing purposes. It has only been once previously 

 recorded from the British Isles (from East Norfolk, by Mr. E. 

 Gurney in 1907), but the species is well known on account of 

 the work done on its anatomy by various German scientists — 

 notably the account of the statocysts in the tail of this species 

 (under the name of Anthura gracilis) by Prof. Thienemann. 

 The structure of the sexual stilet of the second pair of pleopods 

 in the male of Cyathura is especially peculiar and interesting, 

 but no description of this appears to have been published. 



The third noteworthy species of Isopod occurring in this 

 locality is Paragnathia Halidaii (Bate and Westwood), previously 

 recorded by Mr. A. H. Haliday from Strangford Loch in 1847. 

 Since this species was taken at Christchurch it has been found 

 near Plymouth on June 10th and August 18th by Mr. J. H. Keys, 

 F.E.S., while collecting shore insects for the catalogue of the 

 Marine Biological Laboratory, and given for examination to the 

 Bev. Father Morford, who has also examined specimens taken by 

 Mr. Keys some twenty years ago in the same neighbourhood. 

 Dr. W. T. Caiman also has a praniza • taken at or near St. 

 Andrews in 1898, which would seem to belong to P. Halidaii. 

 This species is of the greatest interest on account of its anatomy, 

 which appears to be of sufficient peculiarity to be the grounds 

 for its removal from the genus Gnathia and the formation of the 

 new genus Paragnathia to receive it. P. Halidaii is, in the 

 adult stage, almost terrestrial in habits, and is to be found living 

 in small cavities in the banks ; the males apparently form small 

 holes leading from these, into which they retire in case of danger. 

 The pranizas, like those of other Gnathiidee, are parasitic on 

 fish. 



It is worthy of note that the water in Christchurch Harbour 

 is brackish, and that the species mentioned above are not truly 

 marine, but are found in places where fresh water is mixed with 

 the salt. 



