ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
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praelonga had already been described by MacGillivry as Lepralia 
longipora, but the generic distinction is a good one. Mr. Hincks has 
lately found specimens of Schizoporella subsinuata bearing avicularia. 
There are various other notes on and corrections of the author’s previous 
descriptions. 
y. Brachiopoda. 
Brachial Apparatus of Hinged Brachiopoda.* — Mr. H. S. Williams, 
on making some models of the arms of Brachiopods, found that doubling 
back the lamellae with the spirals attached beyond the bend, caused a 
reversal of the direction of the coil from that presented by it when 
attached before the bend ; he thus produced the exact difference between 
Waldheimia and Anazyga. The experiment showed that the funda- 
mental difference between the brachial apparatus of the Spiriferidae and 
Terebratulidae does not merely consist in the presence of a calcified 
spiral in one and its absence in the other, but in the fact that in the 
Spiriferidae the primary lamellae are continued directly into the spiral 
coils, while in the latter the primary lamella on each side is doubled 
back upon itself to near the position of the mouth, whence the spiral 
part of the arms begins ; the reversal in the direction of the coils of the 
spiral results from this reflexion of the primary lamella. 
Arthropoda. 
a. Insecta. 
Insect Embryology.! — Mr. W. M. Wheeler has chiefly studied the 
Orthoptera, and more particularly Xiphidium ensiferum. The eggs of this 
Insect are laid in the willow-galls produced by a Cecidomyia. In it, as 
in most Orthoptera, there is an invaginate gastrula. The blastopore 
extends nearly the whole length of the germ-band, and is bifurcated 
posteriorly. Later on, a remarkable migration of the embryo compli- 
cates the study of the complex embryonic membranes ; the embryo sinks 
down into the yolk, and by bending comes to lie on the dorsal side with 
its ends reversed, its head being towards the posterior or larger end of 
the egg ; the embryo next moves back into its original position on the 
ventral side of the yolk, and bends back so as to lie as it did at first. 
This second migration, however, is not through the yolk, but on the 
surface, over the posterior end of the egg. 
The author thinks that these movements of “ blasto-kinesis ” are of 
physiological use ; the rapid growth of the embryo probably leads to 
contamination of the yolk, so that there is an advantage in a change of 
position. 
The embryonic membranes of Xiphidium, are very numerous ; there 
is a serosa which covers the entire yolk, and an amnion which covers 
the ventral surface of the embryo. A most remarkable organ is the 
indusium to which the amnion adheres ; it begins as a disk of cells 
anterior to the embryo, is for a time connected with the head lobes of 
the embryo, and again becomes free, when it forms a double body which 
lies in front of the embryo. 
* Proc. Kochester (N.Y.) Acad. Sci., ii. (1893) pp. 113-8 (7 figs.). 
t Journ. of Morphology, viii. No. 1 (1893). See Amev. Natur., xxvii. (1893) 
pp. 745-9. 
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