ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
833 
traces the gradual complication of life-history on to the Tmniidae, and 
finally to EcJiinobothrium, whose liberated joints persist for some time 
and even increase in size. “ The development of the Acalephse may be 
defined as alternation of generations which in certain cases by contrac- 
tion and abbreviation becomes metamorphosis ; while the development 
of the Cestodes is to be interpreted as metamorphosis, which by the 
individualization of certain products of growth may give rise to variously 
complicated forms of alternation of generations.” The sporocysts and 
redirn in the development of Bistomum are heterogenic, sporogonic 
larvae, with parthenogeiietic or paedogenetic reproductive cells ; they are 
morphologically equivalent to the cercariae, as the latter are to the 
cysticercoids of Cestodes. Claus elaborates these comparisons, and 
brings the life-histories of Trematodes and Cestodes into relation with 
the phylogenetic development of their hosts. 
Helminthological Notes.^ — Dr. P. Sonsino discusses those species of 
Bistomum which are allies of B. conus Creplin. The genus Bistomum 
s. str. is characterized by the position of the genital aperture between 
the oral and the ventral sucker. A subgenus Bicrocodium is then distin- 
guished, in which the intestinal caeca are prolonged as far as the posterior 
end of the body. Within this subgenus the members of one section 
have terminal posterior testes, behind the oviducal folds and ovary, and 
one behind the other. Finally, the section thus specified includes the 
group of which B. conus is type. In these the ventral sucker is smaller 
than the oral, the short oesophagus bifurcates far in front of the ventral 
sucker, the anterior fourth of the body has a markedly conical form, and 
all the members live in the bile ducts of carnivorous mammals or of 
man. The testes are ramified in B. endemicum and B. sinense, lobed in 
B. conus and B. felineum, aggregated in D. campanulatum and B. con- 
junctum, doubtful in B. truncatum. 
Parasites of the Salmon, t — Herr F. Zschokke has studied the para- 
sites of the salmon, partly with the hope of thereby verifying the 
statement that the fish fasts as it ascends the rivers, and even after 
spawning is over. In forty-five salmon from the Rhine, eleven species 
of parasites were found, which were almost wholly the wonted guests of 
marine hosts, e.g. Agamonema ca]psularia, Ascaris clavata, Bistomum 
varicum, B. reflexum, Tetrarhynchus solidus, Wiynchdbothrium paleaceum, 
&c. The author found a new species of Bistomum, B. miescheri ; he 
identified Boihriocephalus infundihuliformis and B. prohoscideus, and 
dissents from Kiichenmeister’s conclusion that the salmon is the prin- 
cipal intermediate host of B. latus, for no very young larvm of this 
species were present. It is noteworthy that no parasites occurred 
below the pyloric caeca, a fact which suggested that the fasting fish loses 
in the river many of the guests which are found in the intestine during 
marine life. Notes on the eleven parasites are communicated. 
Peculiar Tetrarhynchid Larva.J— Herr E. Lonnberg found in the 
abdominal cavity of a Gadus virens a single example of the Tetrarhynchus 
* Atti Soc. Tosc. Sci. Nat., vi. (1889) pp. 273-85. 
t Verb. Naturf. Gesell. Basel, viii. (1890) pp. 761-95 (1 pi.). 
X Bihang til Svenska Vet. Akad. Handlingar, xv. 4, No. 7 (1889) 48 pp. (3 pis.). 
See Centralbl. f. Bakteriol., vii. (1800) p. 346. 
