ZOOLOGY AND BOTANY, MICROSCOPY* ETC. 
725 
soon bifurcates. What have previously been taken to be testes are now 
recognized as pyriform dermal glands which are connected with two 
large excretory canals which open at the hinder end of the body. In 
the anterior region there is a large spherical or oval testis, from which a 
short vas deferens leads to a small penis. The oviduct forms numerous 
loops between the branches of the vitellarium. The hinder ends of 
this latter are not separated, but are united near the end of the intestine. 
The caudal end is divided into one unpaired median and two lateral 
lobes, which again are divided into five smaller lobules, each with a 
small hook. It is clear that Amphibdella has not, as Chatin, its original 
describer, thought, any relation to the Hirudinea, but that it is a true 
Trematode and belongs to the Gyrodactylidte, where it stands between 
Calceostoma and Tetraonchus. 
Helminthological Studies.* — Sig. P. Sonsino reports the occurrence of 
Distomum hepaticum in the nylghau (Portax picta) and in Bos bubalus ; D. 
cavise (?) from Cavia cobaya ; D. magnum in Germs dama , &c. ; D. lanceo - 
latum from Antilope dorcas, Capra hircus, and the ass ; Trichina circum- 
flexa, Trichosoma sp. (?), &c., from Mm decumanus ; Strongylus bifurcus 
from several monkeys ; Distomum simile sp. n. from Python molurus ; D. 
gelatinosum from Thalassochelys caretta ; three tailed species of Distomum 
(s. g. Apoblema ), D. excisum , D. rufoviride , D. ventricosum , from fishes ; 
besides Antliocotyle merlucii, Pleurocotyle scombri , Octocotyle arenatasig. n., 
Trochopus longipes , Calceostoma elegans from the same sources. 
Structure and Development of Distomum cylindraceum.-f — Dr. 
v. Linstow describes this well-known but very imperfectly investigated 
Trematode from the lungs of frogs. Its growth is very slow and 
apparently corresponds with that of its host. The mutual fertiliza- 
tion of two large specimens was observed, but self-fertilization 
seems also probable. The history of the reproductive elements was 
followed in detail, and some glimpse of the segmentation was obtained. 
The eggs pass into the alimentary canal of the frog and out by the 
cloaca, but Braun has also observed the passage of the entire Distomum 
through the amphibian’s nose. In the latter case the parasites die in 
the water, while their eggs are liberated, and this also happens when 
female frogs die from the fatal effects of prolonged copulation. Three 
weeks after the eggs have reached the water, a ciliated sheath may be 
observed round the embryo, but several months pass before hatching 
occurs. The liberated embryo finds its way into Limnsea ovata , becomes 
a sporosac, and forms Cercarise which leave their host about midsummer. 
These Cercarise seem then to enter the larvae of small beetles ( [Ilybius 
fuliginosus'), and cysts containing them are found in the body-cavity of the 
adults. The beetles are eaten by frogs, and the cysts are dissolved in 
the stomach, whence the larval Trematodes migrate to the lungs or to 
other parts of the body. 
Trematodes of Gills of Italian Fishes. :J — Sigg. C. Parona and A. 
Perugia have examined nearly one thousand sea-fishes, twenty per cent. 
* Atti Soc. Tosc. Sci. Nat., vii. (1890) pp. 99-114. 
f Arch. f. Mikr. Anat., xxxvi. (1890) pp. 173-91 (2 pis.). 
t Atti Soc. Ligustic. di Scicnze Nat. e Geogr., i. (1890) 14 pp, See Centralbl. f. 
Bakteriol., viii. (1890) p. 310. 
