Four species of Microcotyle. 225 



3. The cliaracter of tlie armature of tlie genital orifices includiijg 

 that of tlie Vagina which in some species is double. 



4. The structure of the suckers about the mouth, especially as 

 to whether they are partitioned or armed with teeth. 



5. The number, form and size of the eggs. 



6. The number and arrangement of the testicles. 



Of all these probably the least variable for any given species 

 are the form of the eggs and the character of the framework of 

 the suckers of the caudal disc. 



31icroeotijJe 2)!P'(i(/i^ff2yfioriis n. sp. 



A few examples of this form were found attached to the gills 

 of the Pomp an {Trachinotus caroUnus). 



The worm is quite small measuring 4 to 5,40 mm in length by 

 0,6 to 1,0 in breadth. Posteriorly, it spreads out into a delicate thin 

 sucker bearing foot which extends gracefully about an equal distance 

 on each side and measures transversely 1,60 to 2,60 mm. It has a 

 double row of spiny suckers along its free margin. These are 

 elevated on pedicels and vary curiously among themselves, for while 

 about forty of them are arranged with long chitinous stalks like a 

 pair of tongs, the rest about sixty-two in number, have no such 

 stalks. These two groups are sharply separated, the stalked ones 

 occupying one side of the foot while the unstalked begin about 

 the middle where they leave off and extend to the otlier angle of 

 the foot. 



Otherwise, the body is smooth and unarmed. It is narrow and 

 elongated and flattened as shown in the drawing and its marginal 

 portions are occupied from the foot nearly to the anterior end by 

 masses of brown vitellarian lobules. Scattered every where and 

 even extending into the foot, there are pigmented cells which are 

 very conspicuous. 



At the anterior extremity, there is a small unguarded mouth 

 which opens into a mouth cavity provided on each side with a 

 muscular sucker measuring 0,11 X 0,05 mm. These suckers diverge 

 anteriorly but approach one another closely behind being separated 

 by the pharynx. They are elliptical and unperforated and form 

 part of the wall of the mouth cavity. The edges of their orifices 

 are set with a Single row of minute chitinous spines, like teeth, 

 and there is an indistinct transverse partition dividing the cavity 

 into two loculi. In section they are composed chiefly of radial 



16* 



