24 PROCEEDINGS OF THE NATIONAL MUSEUM VOL. 73 



MINUTHORCHIS, new genus 



(Mtw^w, to diminish) 



Body oval, thickish; oral sucker terminal; ventral sucker weak, 

 close to oral sucker; pharynx adjacent to oral sucker; no esophagus; 

 intestinal rami extend to posterior end of body. Testes near the 

 lateral margins, transversely placed, and in the posterior half of the 

 body ; ovary behind testes, near the median line ; vitellaria marginal ; 

 uterus voluminous, filling the interior of the body from the ovary 

 to the genital pore, which is at the posterior edge of the oral sucker. 



Genotype. — Minuthorchis sanguineus^ new species. 



MINUTHORCHIS SANGUINEUS, new species 



Figures 53-56 



This genus and species is based on a single distome found in the 

 intestine of a laughing gull {Larus atricilla)^ July 18, 1911. 



The living worm was oval in outline, thickish, upper surface firm, 

 lower surface soft and yielding. The color was blood-red. The 

 dorsal surface was covered with minute papillae. The papillae on 

 the anterior portion of the body are pointed, posteriorly they are 

 blunt. They are not distinguishable in the mounted specimen. With 

 but the slight pressure of the cover-glass to affect the dimensions 

 the length was 7 mm., the breadth 5. At first only one sucker, the 

 anterior, was seen. Later the ventral sucker was distinguished. It 

 lies close to, and is of about the same size as the oral sucker. The 

 uterus was very conspicuous, its voluminous folds ventral, and 

 extending from the posterior to the anterior end. The ova in the 

 posterior folds were yellow, becoming increasingly darker anteriorly, 

 those at the anterior end being dark brown. In the living worm 

 the ova appeared to be long-elliptical, and about 0.11 by 0.04 in the 

 two principal diameters. 



Dimensions in balsam: Length 8.8 mm.; breadth 5.6; oral sucker, 

 length, edge view, 0.24, breadth 0.46; ventral sucker, length 0.36, 

 breadth 0.45 ; pharynx, length 0.24, breadth 0.18. Most of the ova are 

 collapsed, and therefore much narrower than uncoUapsed ones, the 

 shorter diameter being less than half the longer. An uncollapsed 

 ovum measured 0.088 by 0.047, and another 0.090 by 0.045 in the two 

 principal diameters. 



The mouth is directed anteriorly; the pharynx is pyriform with 

 the smaller end anterior. In the mounted specimen the anterior 

 half of the pharynx is embraced by the oral sucker. The ventral 

 sucker is separated from the oral sucker by a distance approximating 

 its own shorter diameter. It is elliptical in outline, the longer 

 ■diameter transverse, with weak musculature. The intestinal rami 



