ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 293 



species in question was almost tiliform with a lancet-shaped head, which 

 showed a shallow incision on each side. It is evidently the larva of 

 some Bothriocephalid, but the feeding- experiments undertaken in the 

 hope of rearing (in the dog) the tapeworm stage did not yield a satis- 

 factory specimen. 



Histogenesis of Gonads of Taenia pisiformis.* — R. T. Young 

 regards it as prol)al)le that the reproductive organs are developed in situ 

 from the parenchyma There is no evidence of specificity of cells. 

 Apparently any cell may partake in the formation of any organ. An 

 epithelium is present in some adult organs, absent in others, being here 

 directly metamorphosed to form a cuticula. Mitosis seldom occurs save 

 in later cleavage stages and in an abortive condition in gametogenesis. 

 Evidence of its degeneration is afforded by the abortive mitoses in 

 gametogenesis and by its infrequent and irregular occurrence elsewhere. 

 There is very strong evidence that amitosis occasionally occurs, while 

 nuclear development from chromidia is probable. Formation de novo 

 may occur, but there is no positive evidence. 



The development of the germ-cells is much abbreviated. Polar 

 bodies are not formed, and the structure of the spermatozoa is apparently 

 very simple. A yolk-cell is attached to the oocyte in the oviduct or the 

 uterus. Early cleavage follows two types : in the first, a fusion nucleus 

 divides amitotically ; in the second, the pronuclei break up before 

 fusion to form the cleavage nuclei. 



Studies on Trematodes.f — (t. A. and W. G. MacCallum have made 

 a careful comparison of the species of Mkrocotyle. small parasites of the 

 gills of marine fishes, and add four new ones to the list, M.jjijragra- 

 phorus, macroura, eueides, and acantlwphaUus. The important features 

 in determining species are the form of the body and the relation of the 

 caudal disk ; the numl)er and skeletal framework of the suckers of the 

 caudal disk ; the genital armature ; the oral suckers, whether partitioned 

 or armed with teeth : the number, form and size of the eggs ; and the 

 number and arrangement of the testes. In another communication 1 

 they deal with Aspidogader riiigeiu (Linton), and A. kemosfoma sp. n., 

 describing, for instance, the remarkable ventral sucking disk and the 

 single testis. 



Fluke from Penguin's Gall -bladder. § — K. I. Skrjabin describes 

 Meforchis pinguinicola sp. n., a small fluke from the gall-bladder of 

 Spheniscus demersus (South Africa). The ventral sucker is in the 

 anterior third of the body ; the receptaculum seminis is consideral )ly 

 larger than the ovary ; the oesophagus is present ; the yolk-glands 

 begin about half-way between the mouth and the ventral suckers. 

 These are among the characters which distinguish this new species from 

 others previously described. 



* Zool. Jahrb., XXXV. (1913) pp. 355-418 (4 pis.). 



t Zool. Jahrb., sx:xiv. (1913) pp. 323-44 (10 figs.). 



X Zool. Jahrb., xxxiv. (1913) pp. 245-56 (4 figs.). 



§ Centralbl. Bakt. Parasitenk., Ixvii. (1913) pp. 527-31 (1 fig.). 



June ISth, 191o x 



