Entozoa of British Marine Fishes. 91 



tapcriiifr toward"* cucli end. Lcnjitli "Sr-rol luiii. The 

 section is approxiiiuitely cireuliir. The cuticle is unarmed, 

 hut very faint tiansverso wrinkles ap[)ear on the surface. 

 The oral sucker is suhterminal, j^lobuhir, with a diameter of 

 16 mm. (in a specimen of lcn<^th 15 mm.). The ventral 

 sucker is somewhat prominent, globular, and lies in front of 

 the middle of the body ("57 mm. from anterior end) ; its 

 diameter is "23 mm. Both have circular a|)ertures. 



There is a large muscular pharynx, almost globular, with 

 a diameter of '08 mm. The oesophagus is extremely short 

 and the intestinal bifurcation takes place immediately behind 

 the pharynx. The diverticula are wide, irregularly dilated, 

 and extend to the posterior extremity of the body. The 

 excretory system resembles that of Deroyenes variciis. 



The testes arc obliquely placed behind the ventral sucker; 

 they are two ovoid bodies, with a maximum diameter of 

 •12 mm. The ovary is more nearly globular : diameter 

 •10 mm. It is situated almost midway between t' e ventral 

 sucker and the tip of the tail. Behind it lies a pair of large 

 vitelline glands having the same structure and disposition as 

 in Derogenes varicvs The uterus is much convoluted and 

 fills a large portion of the body. The eggs are very numerous 

 and rather small, ovoid in shape. Size OSl-O^S mm. x 

 •014-016 mm. 



There is a large ovoid vesicula seminalis lying on the same 

 level as the ventral sucker and dorsal to it, measuring 

 •23 X -17 mm. From it issues a somewhat narrow ductus 

 ejaculatorius, leading forward to the penis-sac. The duct is 

 surrounded for two thirds of its length by numerous 

 prostate-gland cells lying free in the body-substance. The 

 penis-sac resembles that in Deroyenes varicus. It is some- 

 what pear-shaped or almost globular. The aperture is 

 situated in the mid-ventral line at a distance of "21 mm. 

 from the edge of the oral sucker. 



Distomum sp. (PI. III. fig. 12 ; PI. IV. fig. 13.) 



I'rom the muscles &c. of Cuttus bubalis. 



W bile Cdlltcting one day I observed a Cot/us lying in a 

 small rock-pool. I approached it cautiously, but it seemed 

 unaware of my presence until 1 seized it, and even then its 

 struggles to escape were feeble. In a tank it took no notice 

 of food or objects placed near it, but lay torpid. It appeared 

 to be blind. On dissection the cause was revealed. The 

 whole body, skin, muscles, bones, and the layers of the eye 

 were impregiuited with small masses of black pigment. 



