found on the South Coast of Devonshire. 6/ 
are two long arms, with very large oblong-oval hands, furnished 
with a strong spine on the inside, and a long moveable fang, 
which is capable of closing upon the spine, in order to secure its 
prey : the front of the hand in some is also narrowed and elon- 
gated into a spine; the second and third joints of the body are 
each provided with a pair of flat oval fins ; the three posterior 
joints are each furnished with a pair of long, slender legs, with a 
single hooked claw ; the hindmost are the longest, and originate 
from the extremity of the body, the animal being destitute of 
tail. 
Length rarely exceeds three quarters of an inch, and seldom so 
much : colour various, sometimes red, but more commonly pel- 
lucid olive green. 
The female differs in possessing several plates, or valves, be- 
neath the body, situated between the two pairs of fins : the office 
of these is to carry and protect its eggs or young, at which time 
they extend very considerably, and form a kind of pouch. We 
have seen this receptacle distended with ova from fifteen to 
twenty, readily distinguished through the transparent plates. In 
this part a very strong pulsation is observable. 
While examining a female in a watch glass of sea water under 
a microscope, we were agreeably surprised to observe not less 
than ten } T oung ones crawl from the abdominal pouch of the pa- 
rent ; all perfectly formed, and moving with considerable agility 
over the body of the mother, holding fast by their hind claws, 
and erecting their heads and arms. 
On a small species of Fucus (the name of which was not noted) 
a vast number of these curious insects were collected, of both 
sexes, and of all sizes. When at rest they only held by their hind- 
claws; in motion, the arms were also used, and the progression 
K ( 2 was 
