154 RESEARCHES IN HELMINTHOLOGV AND PARASITOLOGY. 



generally of much lighter color and more robust character than the 

 males. In both sexes the body is most attenuated anterior!}', but in 

 the female the body is nearly as thick at the posterior extremity as 

 it is at the middle. Some of the smaller males are pale brownish- 

 white, but most of them, from the smallest to the largest, are of 

 various shades of brown to chocolate-brown. The females are pale 

 brownish to darker brownish. In both sexes the head forms a con- 

 vex, whitish eminence, encircled by a narrow black ring, from which 

 a band of brown extends dorsally and ventrally along the body. 

 The posterior end of the body is likewise of darker color than the 

 part just in advance. 



The tail of the male makes a spiral turn inwardly, and is furcate. 

 The forks are short, curved, slightly divergent, blunt conical pro- 

 cesses. Just in advance of their conjunction internally there exists 

 an inverted crescentic fold of browner color than the contiguous 

 parts, and immediately in advance is the genital pore. The interval 

 of the caudal forks is smooth or free from papillae. 



The tail of the female appears truncated : is bluntly rounded, 

 feebly clavate, or slightly thicker than just in advance, and nearly 

 as thick as the middle of the body. It presents a terminal pore, 

 marked by a brown spot and encircled with a brown ring. 



Under a moderate magnifying power the brown integument is 

 minutel}' mottled with whitish spots, and it exhibits fine longitudinal 

 and diagonal striation. In sunlight it is beautifully iridescent, as 

 in the earth-worm. 



The worms are still quite lively. When disentangled and left 

 alone they soon become again knotted together in a compact rounded 

 mass, as at present, with the heads divergent and writhing so as to 

 remind one of the head of the fabled Medusa. 



Prof. Leidy then directed attention to several other specimens 

 which had been sent to him for information. One of these is a 

 bunch of tapeworms, 15 individuals of Tcniia diniinuta, from the 

 intestine of a rat. The other is the liver of a rat with a multittide 

 of cysts the size of large peas, containing Cysticercus fasciolaris. In 

 a letter accompanying the specimens Dr. John R. Hewett states 

 that last spring he had examined about 500 rats {Mtis decumanus^ 

 in Carroll county, Md , and only in half a dozen instances did he 

 find the liver free from the parasite. 



[February. 1879. No. 469. See Bibliography.] 



On Ihthrioccphalits Latus. — Prof. Leid\- exhibited specimens of a 

 tapeworm which had been submitted to him for determination by 



