ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
333 
Avian Entozoa.* * * § — Dr. E. Linton lias a report on the entozoic para- 
sites of the Birds examined during a natural history survey of the 
lakes and streams of the Yellowstone National Park, Wyoming, the 
trout of which are much infested by parasites. The most interesting 
new form described is a Cestode parasitic in the duck CEdimia americana , 
and called Epision ; the anterior part of the body is singularly modified 
into an organ for absorption and adhesion. A few species collected in 
Mexico are also described in this paper. 
7. Platyhelminthes. 
Monograph of Turbellaria of Black Sea.j - — Dr. Sophie Pereya- 
slawzewa divides her monograph into three parts, the first of which deals 
with the anatomy, the second with the embryology, and the third w r ith 
the genera and species of the Turbellaria of the Black Sea. 
The author objects to the term Acoela, which she replaces by 
Pseudoacoela for several reasons ; the name leads to an impression which 
has been the cause of some of the errors of modern students of Turbel- 
laria ; the facts of embryonic development show that the “ acoelism ” 
is by no means a primary phenomenon, as some authors have stated ; 
anatomical study and that of living animals show that it does not exist 
in adult Acoela. Embryonic development proves conclusively the exist- 
ence of the gastric cavity in the embryo of the Acoela. 
The genera described in the tribe Pseudoacoela are ScMzoprora , 
Aphanostoma, Convoluta, Darwinia [g. n.], Macrostoma , Promesostoma , 
Proxenetes , Hyporhynchus, Macrorhynchus , Schultzia, and Opistoma ; of the 
Alloiocoela, we have Acmastoma , Allostoma, and Monotus. A number of 
new species are described. 
Distoma Cysts in Heart of Fish.J — Dr. 0. Zacharias found that the 
heart of a Coregonus mursena caught in Lake Plon was covered with 
little white dots. These were present in the anterior and posterior 
chamber, and also in the bulbus. Microscopical examination showed 
that these little bodies were cystic forms of a Trematode. There were 
altogether from 200 to 300 of these cysts. 
Ectodermic Tissues of Cestoda.§ — Prof. N. Zograf brings forward 
some evidence in favour of the view that there is a true ectoderm in adult 
Cestodes and in the six-hooked embryos. He hopes that those who are 
not satisfied with his demonstration will at least allow that certain facts 
which appear to prove the absence of this layer are the results of in- 
correct observation ; the existence of animals without ectodermic tissues 
he regards as a paradox. 
Development of Cercaria of Helix hortensis.|| — Prof. F. Bloch- 
mann comes to the conclusion that the larvae of Distomum caudatum 
passed with the faeces of the hedgehog ( Erinaceus ) make their way into 
the snail ( Helix hortensis ), where they attain their cercaria-stage ; when 
* Proc. U.S. Nat. Mus., xv. (1892) pp. 87-113 (5 pis.). 
f Odessa, 1892 [1893], xx. and 303 pp., 16 pis. 
X Centralbl. f. Bakteriol. u. Parasitenk., xii. (1892) pp. 752-3. 
§ Arch. Zool. Exper. et Gen., x. (1892) pp. 331-44 (1 pi.). 
|| Centralbl. f. Bakteriol. u. Parasitenk., xii. (1892) pp. 649-52. 
