43 



Suckers. — There is a sucker at each end of the body, as 

 in all leeches. The anterior sucker surrounds the mouth, and 

 is hoodlike. It almost certainly represents 6 segments. There 

 are no eyes apparent in any of the specimens. This is 

 peculiar, since B. torpedinis bears six distinct eyes on what 

 is considered to be the fifth segment of the anterior sucker. 

 The posterior sucker is twice the size of the anterior, and is 

 in diameter about equal to the width of the abdomen at its 

 broadest part. Its concave surface is covered witfe small 

 papillae. 



Segmentation. — (A description of B. torpedinis, for com- 

 parison with the following, is given by Apathy, 1888, by 

 Blaiichard, 1894b, and, in English, external characters 

 only, by Harding, 1910.) For notation see text figs. 

 1 and 2: — 



(a) Neck. 



A. Head. 



fa) Anterior sucker 1 _ 



/7 i q n t 4- i 6 segments. 



( ij J 6 small annuli present in most genera ) b 



B. Peeclitellum. 



9 annuli, representing ... ... ... 3 segments. 



C. Clitelltjm ... ... ... ... 3 segments. 



Each of the 3 segments, which are of about equal 

 size, is composed of 2 annuli. In the first and third 

 segments the first annulus is larger than the second. 

 In the second segment they are of equal size. The 

 male genital aperture opens between the two annuli 

 of the second segment, and has projecting tumid lips. 

 The female genital aperture opens on the first annulus 

 of the third segment. Both apertures are ventral. 

 The cliteilum is covered by the preputial fold as far 

 anteriorly as the second annulus of the first segment. 



<(£) Body or Abdomen. 



A. Testis region and caecum region taken together. 



12 segments. 

 Each of the 12 segments is composed of 3 annuli, 

 except the first, which acts as a prepuce and is only 

 divided into two. The remaining 11 segments bear 

 each a pair of respiratory vesicles, one on each side, 

 bordering the first annulus of the segment. In B. 

 torped'nis every annulus of these segments bears a pair 

 of lateral foliaceous branchiae, making 33 pairs in all, 

 but in B. australis there are but 31 pairs of gills, the 

 first annulus of segment 2 of the abdomen, which bears 



