1891.] Zoology. 53 
ZOOLOGY. 
Abnormal Repetition of Parts.—Bateson has figured’ some 
interesting cases of monstrosities of this sort. In Cancer pagurus he 
nds an external maxilliped which has been converted into a pincer 
like that of the large claw. In other specimens of the same species he 
finds three specimens in which the pincer has a tendency to duplicate 
itself, as is well known to those who have studied these malfor- 
mations. Another instance is a specimen of Chrysomela banksii, with 
three tarse on the right posterior leg. In aspecimen of Antedon rosacea 
a pair of the arms show a branching into four at some distance from the 
body. The last case isa pilchard with an abnormal number of scales, 
No discussion is given of these instances, but Mr. Bateson has in pro- 
gress an essay on the variation of multiple parts. 
The Embryology of Spiders.—K. Kishinouye has been study- 
ing the development of some Japanese spiders. His descriptions of 
the early stages? are to be regarded as confirmative rather than making 
an important advance. At one stage he finds the yolk free from 
nuclei, the germ-layers arising later from the primitive cumulus and 
the posterior cloud of Claparéde. He differs, however, in some points 
from Claparéde and others in the interpretations of the early surface 
views. Among the interesting points brought out are the following : 
The first abdominal segment has no appendage at any stage. The 
lung books are developed in the base of the appendages of the second 
abdominal segment, in exactly the way necessary to support the view 
of their homology with the gill books of Limulus. An abortive trachea 
develops in the same way from next appendage. The coxal glands are 
own to consist of a ccelomic pouch and an ectodermal duct,—a fact 
which goes far to support their homology with nephridia, and to lessen 
the weight of Eisig’s argument. The author is convinced that the 
malpighian tubes are not ectodermal; he thinks them mesodermal, 
but apparently is not familiar with the results of those authors who 
assign them to the entodermal structures. Some facts additional to 
those of Locy are given regarding the development of the eyes. 
stecoral pocket is regarded as developing from an unpaired posterior 
ccelomic pouch. 
1 Proc. Zool. Socy. London, 1890, p. 579- 
* Journal of the College of Science, Imperial University, Japan, Vol. IV., 1890. 
; i 
n3 
