72 CONTRIBUTIONS TO AMERICAN HELMINTHOLOGY. 



The head does not measure more than 0.5 mm. across in any of 

 my preserved specimens, nor in fact does any part of the chain. In 

 life it is very variable in form, and bears a distinct unarmed rostellum, 

 which is frequently completed retracted, so as to escape notice, but 

 acts much like a fifth sucker. This is merely indicated in Yan 

 Beneden's figure, ^^ and its existence is negatived in Diesing's and 

 Dujardin's descriptions. 



The only ripe proglottides observed were mostly of the form repre- 

 sented in Fig. 15, and measured O.i x 0.16 mm. Instead of containing 

 a series of capsules in pairs with their contained embryos, two or 

 three capsules at most were observed, with six or seven embryos 

 altogether. These measured 0.027 x 0.018 mm. 



NEMATODES. 



ASCARIS ADUWCA. Rud. 



A statement occixrred in the "American Naturalist" in the course 

 of last year, as to the prevalence of an Ascaris in the intestine of the 

 American Shad — Alosa sapidissima, Storer. This was probably A. 

 adunca, R. I have several specimens taken in last winter from 

 Portland fish, which undoubtedly belong to this species. 



The only other reference to a round worm from the American 

 Shad of which I am aware is by Dr. Leidy, who records^ Agamonema 

 capsularia (V), Diesing, as free in the intestines. This, in spite of the 

 "undivided lip," is probably the young of A. adunca, the "obtusely 

 conical, minutely mucronate tail," arguing for this. Molin^* describes 

 " Nematoideum Alausse " also with mucronate tail, but with a four- 

 papillate mouth from the European Shad, but considers that the 

 absence of lips forbids its reference to A. adunca. The metamorphoses 

 of the mouth-parts in Ascaris are still insufficiently known, but what 

 has been already established ^ does not exclude the possibility of both 

 of the above larval forms belonging to A. adunca. 



FiLABIA TRIAENUCHA, U. Sp. 



A single female specimen of a worm belonging to the genus FUaria 

 was found in the upper part of the proventriculus of each of the 



a^Mem. sur les Vers Intest., PI. XXII., Fig. 4. 



83 Proc. Ac. Sci. Phil., VIII., p. 55. 



34Sitz. d. k. Akad. Wien., XXXVIII., p. 31. 



85 Schneider Monog. der Nemat., p. 294. 



