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AUSTRALIAN HIRUDINEA, I., 





Fig.2.— Glossiphonia australiensis, sp.n. 



Anterior end, showing the position of 



the eyes. 



second and third pairs. The second and third pairs of eyes are 

 situated on the third and fourth annuli respectively. They are 



large in size and the members 

 of each pair widely separated. 

 The second and third eyes on 

 each side are closely approxi- 

 mated. The anterior pair are 

 directed forwards and toward 

 the side of the body ; the 

 second pair toward the side 

 and slightly backward ; the 

 posterior towards the posterior 

 region of the body. 



The anterior sucker is con- 

 stituted by seven annuli. The 

 anus is situated on the dorsal 

 surface between the penulti- 

 mate and ultimate annuli. 

 Genital apertures. — When first examining the species I was- 

 inclined to regard the genital apertures as united. This condition 

 obtains in Glossiphonia heteroclita, which is unique in that 

 respect among species of Glossiphonia. On making a closer 

 examination with the aid of sections, I found that the apertures 

 were distinct but separated by a single annulus — the twenty- 

 ninth — which is much diminished in importance. The two 

 apertures open into a depression with tumid lips which lies 

 behind a small clitellum-like swelling on the ventral surface, 

 between the twenty-eighth and thirtieth annuli. Probably one 

 would be enabled to see these separate apertures if an examina- 

 tion were made of a perfectly extended organism. 



The male aperture, then, lies between the twenty-eighth and 

 twenty-ninth annuli, the female aperture between the twenty- 

 ninth and thirtieth. From a study of transverse sections one 

 might readily fall into the error of describing the genital apertures 

 as united, to such an extent has the twenty-ninth annulus been 

 diminished on the ventral surface. 



