CHAPTER OF CRITICISM. 
141 
Saffron Walden, whereby the sum of ten guineas has been proposed to be given 
to the writer of the best essay (to be drawn up from personal observations) upon 
the natural history, economy, and proceedings of the insect injurious to Turnips 
known under the name of the Black or Nigger Caterpillar ( Athalia centifolice ), 
to be illustrated by figures of the insect in its different states, together with the 
result of actual experiments, made for the prevention of their attacks, or the 
destruction of the insects themselves. The essays must be accompanied by 
testimonials of the success of the remedies proposed by the writers, and must be 
forwarded to the Secretary of the Entomological Society, at No. 17, Old Bond- 
Street, London, with fictitious signatures, on or before the fourth Monday in 
January , 1838, when they will be referred to a Committee, to decide upon their 
respective merits, after which, with the permission of the writers, the prize-essays 
and any others of value will be published. 
The prize-essays must be accompanied by a sealed letter, indorsed with the 
fictitious signature adopted by each writer, and including his real name and 
address. 
I am. Sir, 
Yours very obediently, 
London , Jan. 16, 1838. J. 0. Westwood. 
[[From the letter with which Mr. West wood has favoured us, it will be perceived 
that the prize-essays could not be received later than Jan. 22, but as the com¬ 
munication furnishes the information requested by e< Philander ” at p. 45, we 
have thought it best to publish it. We found it impossible to transmit Mr. 
Westwood’s epistle in MS. to “ Philander” in time to be of any service. — Ed.] 
CHAPTER OF CRITICISM. 
Acephalous Mammalia. 
To the Editor of the Naturalist. 
My dear Sir, —In the fifteenth number of your Magazine (Vol. II., p. 490) 
there is notice of a lamb without a head.' These lusus naturae are not so 
extraordinary as your correspondent seems to think. In the process of the 
development of the embryo, one part of the system may be stopped in its 
growth whilst the rest may go on developing in a normal manner. It is on this 
ground that all varieties of monstrous formations can be explained, and thus 
those forms which at first sight would appear to be departures from the laws of 
u 2 
