598 SCIENTIFIC RECORD FOR 1884. 



cial moDOgraph. These "worms are not easily found ; to obtain tbeui, it 

 is necessary to dig with a knife into moist ground, and especially to seek 

 for them about the roots of trees. The fieshwater species are generally 

 found among the leaves of plants, filaments of algae, or confervae, while 

 others are met with in the muddy bottoms of ponds and brooks. 



A rare human Tapeicorm. — At least eight species of tapeworms or 

 intestinal worms of the family Tccniidw have been found in the human 

 body in varying numbers. Of course, the most common are the Tcenia 

 solium and the Tcniia- meiliocancllata, the former being derived ordinarily 

 from pork, and the latter from beef. There is one species of the family 

 — the Tcenia {Eymenolepis) Jlavopunctata — that has only once been tbund 

 in the intestines of man. It was in 1858 that Dr. Weinland discovered 

 some specimens discharged by a child in Boston. Dr. Leidy recently 

 obtained evidences of the same species expelled from a child three 

 years old by a dose of santonin ; tlie specimens, consisting of a dozen 

 fragments, appeared to be portions of three worms, Avhich reached a 

 length of from twelve to fifteen inches or more. Unfortunately the 

 head was lost, but enough remained to identify the species. " The 

 mature eggs are spherical, measure some 0.072 millimeter in diameter, 

 and contain, fully developed, six hooked embryos." 



Although so rarely met with, it was thought by Dr. Leidy to be 

 jirobable that the worm is more common than would be supposed from 

 the rare instances of its observation, and that it has generally escaped 

 notice only " from its suiall size, and from the general ignorance of 

 the distinction, not only of this, but of the ordinary species of tape- 

 worms." Nothing is known respecting the life history of the worm or 

 its other hosts. {Proc. Acad. Nat. Sc. Phila., 1884, p. 137.) 



Xematelminths. 



The orifjin of the eggs and sperm of Ascaris. — The direction of the 

 studies of zoologists nowadays is well illustrated by several very elab- 

 orate memoirs on the genesis of the eggs and sperm in the common 

 intestinal thread-worm of the horse {Ascaris megalocephala). One by 

 Dr. E. Van Beneden on the ovum and its fertilization takes up 375 

 pages; another, by Van Beneden and Julin, on the spermatogenesis, is 

 30 ])ag('S long; and another, also on the spermatogenesis, by Dr. P. 

 Hailez, is 3 i)ages long. The most important of these memoirs is pub- 

 lished in the Archives de Biologic (iv, pp. 265-G40, with 1 pi.). 



Annelids. 



An American fresh icatcr Worm. — In certain rivers of Eastern Amer- 

 ica, beyond the intiow of salt or brackish water, is found a species of 

 tube-making chictobranch worm which is closely related to certain sea- 

 worms, and which has no known relation in fresh waters elsewhere. 



