688 



(Zool. Jahrb. Bd. 13. 1900. p. 409), both referring it to D. ovocau- 

 datum of Europe. I have formerly seen it in abundance. My present 

 specimens, 37 in number, vary in length from 1,61 to 6 and from 

 0,43 to 1,5 in greatest breadth. A few present pictures approximating 

 to that given by Loo s s (Die Dist. etc. 1894. Taf. III. fig. 49) but they 

 are shorter and more compact in proportion to their breadth, being 

 broad and deep at the centre and gradually narrowing towards the 

 ends which are rounded. Sections are nearly circular. 



The cuticle is smooth and perforated by numerous skin-glands. The 

 ventral sucker is larger than the mouth-sucker and in the middle of 

 the ventral surface. The mouth passes into a pharynx which is suc- 

 ceeded by a short oesophagus and then the lateral coeca, broad and 

 wavy, extending to the extreme posterior end. The excretory bladder 

 passes from the terminal pore to the ventral side and divides, just 

 behind the ventral sucker, into ventro-lateral vessels which run for- 

 wards and unite above the mouth-sucker, just anterior to the trans- 

 verse band of the nervous system. Most of the posterior half is taken 

 up by the genital glands — the anterior testis being often close be- 

 hind and to one side of the ventral sucker while the vitellaria are in 

 the extreme posterior end. In all the testes are oblique (not side by 

 side) and in three quarters of them the anterior testis is on the right 

 side, the posterior on the left. Inlialf the ovary is in the median line; 

 when slightly displaced it is on the same side as the posterior (nearest) 

 testis, generally left. The vitellaria have five follicles on the left, 

 four on the right — in only two specimens out of eighteen were the 

 five on the right and then the ovary and posterior testis were also 

 slightly towards the right. When the ovary is in the centre the shell- 

 gland is behind it; when the former is to one side the latter is behind 

 and towards the other side. The Laurer's canal runs upwards and 

 backwards to the surface. A very noticeable difference from the 

 European species is the short space between acetabulum and first 

 testis, limiting the number of transverse folds of the uterus in this 

 region. The genital pore is immediately behind the mouth sucker, 

 underneath the pharynx. There is a short sinus which receives the 

 small vagina and ductus ejaculatorius, the latter succeeded by a ve- 

 sicula seminahs. The eggs are yellow, have a big rounded end, and 

 then slowly taper towards the little end, which rounds down to the 

 base of the filament. The latter appears shorter than the egg but 

 towards the end it becomes very thin and bent or twisted so that it 

 is hard to get a straight measurement. Eggs generally about 0,063 

 X 0,018 (sometimes one as large as 0,071 X 0,021), filament about 

 0,056. 



