266 Praniza Edwardii. (CHAP. Xv. 
nutest animal is equal to the largest, in point of value and 
interest. The Anceus creeps on the bottom of the sea, but it 
swims with great rapidity—propelling itself forward by the 
quick motions of a series of ciliated fins placed beneath the 
tail. The Anceus, in its young state, is parasitical, and is 
furnished with a sharp process at the apex of the anterior 
lip, to form a strong lanceolate organ, with which the ani- 
mal cuts its way through the skin of the fish on which it 
preys. It was at first thought that Praniza Edwardii was 
a female, and that the male had not yet been discovered. 
On seeing this stated in the number of the “ Sessile-eyed 
Crustacea” in which the Praniza was noticed, Edward wrote 
the following letter to Mr. Spence Bate: 
“My pear Sm,—Some considerable time ago, I sent you, among 
other things, what I believed to be two distinct species of Anceus, the 
one being considerably smaller than the other. Of the lesser, there 
were several specimens; but of the larger, only two. The answer 
which you gave me was, that they were Anceus mazillaris. At this I 
was somewhat disappointed. I admit that the larger were of that 
species, but not the smaller. And since I received your last number, 
which treats on this subject, I am now more than ever convinced that 
they are distinct. I consider the smaller specimen to be the male of 
the Praniza Hdwardii. I may be wrong, but that is my conviction. . 
I need not, of course, attempt to point out the distinctions to you; 
but perhaps you will allow me to state u few words on the subject, 
and what makes me think that he is the male of Praniza Edwardii. 
“In the first place, I would say that this little fellow is decidedly a 
deep-sea species—that is, so far as my experience goes. I have never 
found him but on the old shells and stones brought up by the fisher- 
men’s lines. There he seems to prowl about seeking what he may 
devour—prying into every crevice and corner in search of food, and 
also into the tenantless worm-cases with which these old shells and 
stones are generally incrusted. Now these are exactly the habitats 
and manners of the Praniza Edwardii when adult. Where I find the 
one, I am almost sure to find the other. I have found them together, 
and taken them out of the same worm-tube. But though this does not 
amount to an entire proof, still it helps to strengthen my conjecture 
that they are male and female. 
“Tn the second place, besides the diane disparity in size, the 
mandibles in this species appear to me to differ considerably from 
