200 



S. J. JOHNSTON. 



x 0*542 mm.). The ovary is oval in form, obliquely placed on 

 one side of the middle line, and measures 0*194 x 0*136 mm. 

 It lies only a short distance in front of the testes, the space 

 between being filled by the large gland of Mehlis. The 

 cirrus sac is very elongated and reaches back to the level 

 of the ovary. For the whole length of the ventral sucker 

 it is tubular in form, but behind that point it swells out 

 into a more or less pear-shaped structure, and in this part 

 the coiled vesicula seminalis is contained. The long cirrus 

 is lined by chitinous tubercles or blunt spines (text fig. 8). 

 A number of prostate cells lie in the parenchyma of the 

 cirrus sac in the posterior part of the division lined by the 

 spines, and further back. 



The yolk-gland field begins 

 anteriorly at the level of the 

 ovary some distance behind the 

 ventral sucker, and is confined 

 to the lateral parts of the body 

 down to the posterior end of the 

 testes. From this level the yolk- 

 glands spread inwards to the 

 middle, but stop short some little 

 distance from the posterior end. 

 The follicles are fairly large and 

 round, varying in size from 0*068 

 to 0*106 mm., in diameter. The 

 uterus is short and contains 

 Fig. 8.— Figure combined from comparatively only a few oval 



several longitudinal sections of rv.rmer w r\.r\nn -~~~ 



A. spinulosum showing cirrus etc. ©ggS 085 X 069 mm. 



C.s., cirrus sac; G.p. , genital pore; 



Sp.c, spines on the cirrus (which This species differs from A. 



is represented inverted in its , . , . T .., ... . 



position of rest); v.s., vesicula phcenicopteri, Luhe, parasitic in 



seminalis; V.sh, ventral sucker. a Flamingo Plicentcopterus 



roseus, at Tunis, the only other member of the genus, in a 

 number of easily recognisable characters. In the first place 



