274 
PLATYBDELLA ANARRHICHAE. 
WITH A NOTE, ERRATUM, AND AN APPENDIX. 
By W. HAROLD LEIGH-SHARPE, B.Sc., A.C.P. 
Lecturer in Zoology at the University Tutorial College, London; 
Demonstrator in Biology at Guy’s Hospital Medical School, Ijondon. 
(With ] 1 Text-figures.) 
CONTENTS. 
PAGE 
Platybdella anarrhichae ........ 274 
Note. Galliobdella lophii . . . . . . . . 291 
Erratum ........... 291 
Appendix. Key to the Ichthyobdellidae . . . 291 
Platybdella Anarrhichae. (Diesing 1858, as defined by Malm 1863.) 
Introduction. In a previous paper (1914, p. 217) I gave, in tabular 
form, the features which serve to distinguish the two genera Calliobdella 
van Beneden and Hesse 1863, and Trachelobdella Diesing 1850, which 
Johansson 1898, pp. 672-675 has also given reasons for distinguishing. 
Immediately after the publication of my paper I learned through 
Mr T. J. Evans of Guy’s Hospital Medical School that Dr Herbert 
Henry, when in Scottish waters, had repeatedly found a leech alleged 
to be Trachelobdella on the gills of Anarrhichas lupus. Henry concerned 
himself with Haemogregarina occurring in this fish, and the leeches he 
found were determined by Miss Muriel Robertson as probably Trachelo¬ 
bdella lubrica Grube 1840 ( vide Henry 1912, p. 195). 
I have since received, through the courtesy of Prof. D’Arcy 
Thompson, some dozens of leeches taken from A. lupus and collected 
by Dr Alexander Bowman of Aberdeen. These leeches proved to be 
