Helminth Fauna of the Dry Tortugas. 83 



The absence of a median ventral ridge does not justify the erection 

 of a new species, since only one specimen was seen at the Dry Tortugas; 

 moreover, many of the Beaufort specimens had very faint median ridges. 



Host, Calamus calamus: July n, 1908, 5 fish, 1 trematode. 



Dimensions, life: Length 1.51; breadth, of head 0.42, of disk 0.86, 

 of neck 0.31; pharynx, length 0.14, breadth 0.10; ova, variable, 0.075 

 by 0.045. 



DEONTACOTYLEA. 



Deontacylix ovalis gen. et sp. nov. (Figs. 231-235.) 



Etymology: Siovra, lacking; /outc, a cup. 



A few small trematodes are here described which appear to represent 

 a new genus of certain affinities. It was nearly dark when I began to 

 examine them, so that but few notes were made of the living specimens. 

 They were afterwards stained, some in carmine and some in haematein, 

 and mounted whole in balsam. 



Body long-oval, flattened, tapering gradually to the anterior end 

 and more abruptly to the posterior end. General color white, the 

 branches of the intestine yellow. The mouth is minute, on the ventral 

 side very close to the anterior end. The body is covered dorsally and 

 laterally with minute, short, slender, rod-like spines in transverse rows, 

 the rows about 0.009 mm. apart. There is no distinct oral sucker, no 

 pharynx, and no ventral or other sucker present. The moderately 

 narrow esophagus pursues a somewhat sinuous course to about the 

 anterior third of the body, where it divides into two branches. These 

 branches soon divide into two smaller branches, one extending forward 

 and the other back. These secondary branches are somewhat irregular 

 in outline, being short-sinuate or sacculate with one or more additional, 

 shorter branches. The posterior rami reach to about the middle of the 

 length of the body. Along the margin of the body there is a distinct 

 border, finely granular and more lightly staining than the interior, and 

 separated from the interior region by a light line having the appear- 

 ance of a nerve. That is, 2 lateral nerves can be traced from a short 

 distance behind the mouth, where they form a common band which 

 crosses the esophagus dorsally and sends branches forward to unite again 

 around the mouth, back to near the posterior end of the body. 



The genital openings are close together and close to the posterior 

 end on the dorsal side. A short tube (fig. 231m) leads from its aperture, 

 a little to the left of the median line, to a closely folded, tubular organ 

 which appears to be the uterus. It is crowded with small, granular 

 masses which are probably ova, although they do not look like any 

 trematode ova that I have seen before. When isolated they are ovate, 

 oval-elliptical, and pyriform, and there appears to be a thin shell. When 

 highly magnified each ovum is seen to contain several coarse, granular 

 masses of yolk (fig. 234). The cirrus (or ejaculatorv duct) is short and 

 leads from its opening near the opening of the metraterm to a seminal 

 vesicle near the right border. In some specimens there was a tubular 

 vas deferens without any noticeable enlargement into a seminal vesicle. 

 The vas deferens could be traced forward between the uterus and ovary, 



