Helminth Fauna of the Dry Tortugas. 23 



I. TREMATODES FROM LOGGERHEAD TURTLE. 

 Cricocephalus delitescens Looss. (Figs. 1-3.) 



Zool. Jahrb., xii, pp. 666-667, 759~762, Taf. 31, figs. 76-80. ' 



A single specimen, actively contractile, 4 to 10 mm. in length, is 

 referred to this species, although there are some differences between 

 its anatomy and that of C. delitescens as given b}?^ Looss. Unfortunately 

 the specimen, when stained and mounted, revealed but little of the 

 anatomy, and it was damaged in attempting to section it later. The 

 sketch (fig. i) was made from the stained and mounted specimen, but 

 a few details were added from the fragments of the damaged sections. 

 It will be noted that the intestines lie laterad of the testes, which would 

 point to Looss's genus Pronocephalus. On the other hand the presence 

 of the peculiar structures at the lateral angles of the posterior end of 

 the body, which are the principal justification for the erection of the 

 genus Cricocephalus, are quite distinct in this specimen. The descrip- 

 tion which follows is necessarily incomplete. 



Body long-oval; head blunt, triangular, marked off from the body 

 proper by a distinct muscular eminence; posterior end truncate, with 

 a small sucker at each lateral margin. Oral sucker a little broader than 

 long; mouth with notch on posterior border; esophagus slender with a 

 pharyngeal enlargement at its base and followed immediately by the 

 bifurcation of the intestine. The intestinal rami extend to the posterior 

 end of the body; anteriorly they have numerous short branches, but 

 at their posterior ends, which pass laterad of the testes, the branching 

 is not so evident. The structures at the postero-lateral angles of the 

 body appear to be small suckers. Each sucker consists of a slight con- 

 ical elevation, which, upon magnification, is seen to be shaped like a 

 low frustum of a cone hollowed out into a shallow pit. They are sur- 

 rounded by dense muscular tissue. The genital aperture is ventral at 

 the left side of the neck and near the lateral margin. The cirrus-pouch 

 is long and consists of three portions: proximal, middle, and distal, 

 reckoning from the anterior end. The proximal division contains the 

 retracted cirrus which is surrounded by prostate cells; the middle part 

 is cylindrical and contains the convoluted seminal duct; the distal part 

 is long oval-elliptical in outline, and contains the seminal vesicle, which 

 also is surrounded by prostate cells. Behind the cirrus-pouch is the 

 vas deferens, a comparatively capacious duct lying along the middle line 

 and extending as far as the vitelline glands. The testes are 2, lateral, 

 opposite, and near the posterior end of the body. The ovary is near the 

 antero-median border of the right testis and is situated a little to the 

 right of the median line. It appears to be slightly lobed. The shell- 

 gland is on the posterior border of the ovary between the testes. The 

 vitellaria are lateral and extend for a short distance forward from the 

 anterior borders of the testes. Each gland consists of a cluster of irregu- 

 larly rounded, compact masses. The uterus begins at the shell-gland 

 and passes to the anterior end of the body by a series of transverse folds 

 packed closely together and filling all of the body between the vitelline 

 glands and the anterior third of the body. The metraterm is capacious, 



