Benham. — Tivo Neiv Species of Leech in N.Z. 187 



teristic of the genus^viz., 1, 2, 3, 5, 8 (following Whitman 

 and Blanchard, but Moore counts the preocular region as the 

 first annulus. I have, however, made no attempt to analyse 

 the annulation). The eyes are situated at the edge of the dark 

 pigmented region. 



I find no distinct preocular annulus, nor can I detect in any 

 of the specimens, fresh or preserved, any segmental " sensillse " 

 — hence my inability to define the limits of the somites, which 

 no doubt agree with other species. 



The total number of annuli is 102. The male pore is situated 

 on the extreme posterior margin of annulus 30, so that in a 

 contracted specimen it appears to be between 30 and 31 ; 

 the female pore is between annuli 35 and 36 : or, counting 

 the ventral annuli only, they lie respectively between the post- 

 oral annuli 24 and 25, and 29 and 30 — in other words, in a 

 position typical for the genus. 



The seventeen pairs of nephridiopores occupy the usual 

 position. 



The lower lip is formed by annuli 5 and 6, fused more or 

 less ; while the 4th also comes down the side of the sucker, and 

 part of the way across the ventral surface, but is here indis- 

 tinguishably united with the 5th. 



Internal Anatomy. 



This was examined only by means of dissection of other 

 individuals; not of No. 1. 



The alimentary canal has the usual structure. The anterior 

 sucker leads to the mouth, and is grooved dorsally (fig. 8). 



The three jaws are nearly semicircular ; the oral margin 

 being, however, rather straighter than the aboral or outer mar- 

 gin, which meets it at an angle. The denticles are set along 

 this margin only, very small externally, and increasing gradually 

 towards the angle ; the second and third, at the oral end of the 

 series, being of much greater size (fig. 9). There are forty-eight 

 to fifty of these denticles. 



In H. medicinalis, it may be mentioned, the denticles are set 

 along the entire margin, and though gradually increasing in 

 size as the median plane is approached, they are not so large as 

 those in the present species, and are much more deeply imbedded 

 in the jaw. 



The genital organs (fig. 10) differ in several details from 

 the typical species. There are, as usual, ten testici lar sacs (or 

 testes) on each side, communicating by short vasa efFerentia 

 with the delicate vas deferens running along the body-wall at 

 their outer side. At its anterior end this duct becomes enlarged, 

 and closely convoluted to form a whitish mass, the " epididymis "^ 



