396 ^- A. MacCallüm, 



the ootyp which is surrounded by the shell ^land. From this point 

 tlie tube passes forward along the right inner margin of the vitel- 

 laria to the genital pore. The vitelline ducts, which unite as usual 

 to enter the oviduct by the common tube described, again unite 

 anteriorly to form the vagina which opens dorsally a short distance 

 behind the genital pore. The vitellarium is very voluminous occupying 

 the major part of the body on both sides. The eggs are yellow and 

 fusiform with a chitinous filament at each end, the anterior being 

 much larger than the posterior and very delicate and tangled near 

 its end. 



There are 60 testicles situated near the caudal end of the body 

 from which the large tortuous Vas deferens runs forward to the 

 muscular cirrus already described. The water vascular system is 

 very distinct being composed of large ducts wliich proceed to the 

 end of the disc receiving branches on their way from the surroanding 

 tissues. 



Measurements : 



Length : 4,4 mm. 



Width: 0,8 mm. 



Ova: 0,11 X0,03 mm. 



Length and width of disc: 0,9 X 0j5 '<^^ base. 



Suckers : 48 in number — larger ones 0,05 X 0,07 ; smaller 

 0,04 X 0,03. 



Width of head: 0,47 mm. 



Testes: 60 in number 0,07 mm. 



Hooks at tip of disc: 0,029 mm long X 0,002 mm wide. 



Spines at tip: 0,15 X OjOl mm. 



Oral suckers: 0,04 mm. 



Hooklets around g. p.: 0,05 mm long. 

 Habitat: Gills of yellow Crevalle {Caranx crysos). 

 Location: Woods Hole, Mass. U. S. A. 



Mlcrocotyle angelichtliys n. sp. 



A worm closely related to others to be described but differing 

 in one or two important particulars is found on the gills of the 

 Angel fish, Holacanthus ciliaris, in numbers varying from a few to 

 many thousands or enough to cause the death of its host. 



It is small measuring 4,3 X 0,3 mm with a caudal sucker disc 

 about 1 mm long armed with forty to sixty suckers (Fig. C a). The 



