68 Papers from the Marine Biological Laboratory at Tortugas. 



represent the excretory vessels in the anterior part of the body. The 

 body-wall is rather thick and the musculature is well developed. 



Dimensions of mounted specimen: Length 3.50; breadth 1.12; 

 length of neck 0.88; oral sucker, length 0.48, breadth 0.46; pharynx, 

 length 0.21, breadth 0.14; ventral sucker, length 0.42, breadth 0.48; ova 

 0.054 by 0.027. 



Host, Scarus cceruletts: July 13, 1908, 2 fish, 3 distomes. 



Host, Scarus sp. (This was a parrot-fish having many points of 

 resemblance to Sparisoma abildgaardi.) 



July II, 1908, I fish, 2 distomes. 



Pale red, thickish, with lateral dark lines meeting behind ventral 

 sucker. Dimensions, flattened: Length 5; breadth 2.5; oral sucker 

 0.56; pharynx, length 0.43, breadth 0.35; ventral sucker 0.86; ova 0.047 

 by 0.034. 



July 8, 1908, I fish, i distome. 



Not in good condition. Ova o.og by 0.06. 



The distomes here recorded probably represent different species. 



Host, Scarus croicensis (?): July 8, 1908, 2 fish, i distome. 



Specimen in poor condition. Fusiform, no ova. 



Dimensions: Length 1.12 ; breadth 0.67 ; oral sucker 0.22 ; pharynx 

 0.15; ventral sucker 0.35. 



Host, Scarus croicensis: July 7 and 8, 1908, 3 fish, i distome. 



Dimensions in glycerin, flattened: Length 2.10; breadth 0.77, 

 oral sucker 0.29; pharynx 0.07; ventral sucker 0.49. 



Deradena acuta gen. et sp. nov. (Figs. 158, 159.) 



Distomum sp., from Tylosurtis acus. Parasites of Bermuda Fishes, Proc. U. S. 

 Nat. Mus., XXXIII, p. 115, fig. 62. 



This species bears a superficial resemblance^ to Haplosplanchnus 

 Looss, but the vitellaria are diffuse instead of dendritic. 



Body fusiform, broadest in middle, whence it tapers to each end, 

 the posterior end being rather the more slender. Ventral sucker at about 

 anterior third, nearly twice the diameter of the oral, its aperture narrow 

 and nearly coinciding with the axis of the body. There is a short pre- 

 pharynx and an esophagus. The pharynx is slightly pyriform. The 

 genital aperture is close behind the pharynx and a little to the left of it. 

 The cirrus-pouch proper is adjacent to the genital aperture and is nearly 

 circular in outline. What seems to be the prostatic portion and the metra- 

 term lies on the right side of the ventral sucker. A characteristic striated 

 appearance of the cirrus-pouch, noted in the living specimen, is evident 

 in the mounted specimen, both in the globular portion and in the slender 

 prostatic portion. The rami of the intestine appear to extend nearly 

 to the posterior end. Two glandular bodies at the antero-lateral bor- 

 ders of the ventral sucker (fig. 159 (i) are interpreted to be yolk-forming 

 glands. The vitellaria are dense and diffuse, filling the greater part of 

 the body behind the ventral sucker. They extend about as far forward 

 as the middle of the ventral sucker. In the stained specimen they are a 

 rich reddish -brown, and lie in dense masses between and to some extent 

 over the other organs. There is a single large testis which is somewhat 



