55 



(2) White spots on the dorsal (2) White spots on the dorsal' 



side caused by the absence side caused by the absence 



of black pigment are typic- of black pigment are typic- 



ally : — ally: — 



4 large on the 1st annu- 6 on the 1st annulus of 



lus of each abdominal each abdominal seg- 



segment. ment ; none on the 



8 small on the 2nd annu- other annuli. 



lus of each abdominal 

 segment. 

 4 small on the 3rd annu- 

 lus of each abdominal 

 segment. 



(3) Black pigment dots are ab- (3) White spots on the ventral 



sent from the major part surface : 4 on the 1st 



of the ventral surface, so annulus of each abdom- 



that there can be no inal segment, 

 white spots. 



(4) Eyes, apparently none. (4) Eyes, 6. 



In B. aust ralis the neck region is relatively longer than 

 in B. torpedinis, and the first segment of the abdomen larger. 

 The gills are of a different shape from those of B. torpedinis, 

 and, allowing for preservation, probably smaller, while the 

 respiratory vesicles are relatively much larger. In the place 

 where one expects to find eyes are larger black dots (in two 

 of the specimens), which I regard as merely pigment cells; 

 in any case, these are more than 6 (8 and 9 respectively). 



References. 

 Apathy (1888). Analyse der ausseren Korperform der 



Hirudineen. Mitth. Zoo] . Stat. Neapel. viii., 153. 

 Blanchard (1894a). C'ourtes notices sur les Hirudinees, xix. 



Sur les Branchellion des mers d'Europe. Bull. Soc. 



Zool. de France, xix. 

 (1894b). Hirudinees de Tltalie. Boll. Mus. Zool. 



Univ. di Torino, ix. No. 192. 

 Harding (1910). A revision of the British leeches. Parasit- 

 ology, iii., 130. 

 Leigh-Sharpe (1914). Oalliobdella lophii, Parasitology, vii., 



204. 

 (1916). Platybdella anarrhichae , Parasitology, viii., 



274. 

 Perez and Gendre (1904a). Sur les fibres musculaires du 



Branchellion. Comptes rendus soc. biol. Paris, lvii., 113. 

 (1904b). Sur Tovogenese du Branchellion . Op. cit., 



lvii., 605. 

 Perez (1906). Differenciations tendinenses epitheliales chez 



le Branchellion. Op. cit., lviii., 447. 



Hamilton House, 17, Clyde Street, Redcliffe Gardens, 

 London, S.W., England. 



January, 1916. 



