1881. | Entomology. ; 395. 
studied by Dr. H. Rabl-Rickhard, of the Berlin Museum, with a 
view (1) to determine the cephalic ending of the notochord in its 
relations towards the hypophysis cerebri and the so-called middle 
trabecula, and (2) the origin of the pineal gland. He finds that 
at no period has the embryo of Acanthias a notochord with its 
apex projecting beyond that part of the base of the skull, which 
subsequently becomes the dorsum selle, thus confirming the 
views of W. Miller, Balfour and Parker; though this view is not 
irreconcilable with the view of Reichert, that the notochord of young 
question as to the development of a tail in the human embryo, 
disputes that it has at first a true tail, as it possesses no super- 
numerary vertebre, and in pathology no extra number have ever 
occurred. 
ENTOMOLOGY.’ 
Exuviation 1n Fricut.—Mr. R. McLachlan has recorded a 
skin was shed-in an incredibly short space of time (less than a 
minute), but was almost invariably preceded by a brief period of 
rest. The impatience to fly off after the true wings were with- 
drawn, however, was such that in the large majority of cases the 
sect took wing before the subimaginal skin was fully cast, in 
which case exuviation would be completed on the wing. We 
cannot conceive of the beginning of the process taking place on 
the wing, for there is a period, however short, from the bursting 
of the skin on the thorax to the extraction of the wings from 
their covering, when the use of the wing, it seems to us, is impos- 
sible ; and we can conceive of full exuviation in the air only on 
1 . 
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