42 



A New Species of Leech from South Australia. 



By W. Harold Leigh-Sharpe, B.Sc. (Loncl.). 

 (Communicated by Edgar R. Waite, F.L.S.) 



[Read May 11, 1916.] 



Branchellion australis, n. sp. 



Introduction. — By the courtesy of Dr. J. H. Ash worth,, 

 of the University of Edinburgh, I have examined six 

 specimens of the genus Branchellion forming part of the 

 collection of the Museum of South Australia, Adelaide. The 

 tube containing the specimens bears the label "E129," and 

 attached is a note to the effect that they were collected 

 by W. B. Poole on March 27, 1912, at Port Victor, South 

 Australia, attached to a Skate (liaia lemprieri, Richardson). 



Ail the sjDecimens are alike, but they exhibit somewhat 

 marked differences from Branchellion torpedinis, Savigny, the 

 only established species (vide Blanchard, 1894a). These 

 differences are, in my estimation, of specific and not generic- 

 value only, and for the Australian leeches I propose the name 

 Branchellion australis. 



Bad ij . — The largest specimen measures 35 mm., inclusive 

 of the suckers, and 30 mm. without the suckers. - The large 

 specimen of 7i. torpedinis in the British Museum (Natural 

 History), South Kensington, London, which I have used for 

 purposes of comparison in this paper, measures 55 mm., of 

 which the anterior sucker occupies a little more than 4 mm., 

 the neck 7 mm., the abdomen 49 mm., and the posterior 

 sucker a little less than 5 mm. The two largest specimens 

 are greyish-black in colour and appear to be mature. The 

 smaller specimens are white, having been decolourized by the 

 alcohol in which they have been preserved. The leech is 

 cylindrical, and divided the most sharply of all the 

 Ichthyobdellidae into two distinct regions— a neck region, 

 which is bare, and a spindle-shaped abdomen, the latter 

 carrying laterally 31 pairs of foliaceous branchiae, and 11 

 pairs of rounded, pulsating, respiratory vesicles, described 

 below. As in B. torpedinis, the neck is capable in the mature 

 individuals (Apathy, 1888) of being invaginated into the 

 abdomen, the first segment of which, composed of two annuli, 

 at least, forms a prepuce-like fold surrounding and over- 

 lapping the posterior portion of the clitellum. The leeches- 

 are considerably flattened in the abdominal region, being- 

 elliptical in section. 



