ZOOLOGY. 
CCXXXV 
red colour ; antennse four-articulate, the second and third members very small, 
and the terminal setaceous, flexible by annular articulations ; the last joint of 
the superior pair is thick and fleshy at the base ; body of seven segments, 
broader and less compressed than is usual in its congeners ; caudal segments 
four exclusive of the tail itself, more attenuated than those of the body, but 
larger ; legs fourteen, the four anterior equal and similar, five-jointed, being a 
long compressed thigh with four much shorter articulations, hirsute, and un- 
armed ; the ten posterior legs similar and equal in size, five-jointed, the thigh 
being long and much compressed, followed by three short fleshy joints, (the first 
of which is the shortest,) and by a long and curved member, terminated by a 
nail ; the six posterior legs are directed backward ; the three anterior caudal 
segments with each a pair of swimmers ; the fourth caudal segment has on 
each side a pair of foliaceous styles borne on a two-jointed cylindrical foot- 
stalk ; the tail consists of two foliaceous plates, each terminated by two smaller 
ones, strongly pointed and articulated to the larger ; and is also furnished 
with a second pair of lateral style processes. 
This description differs from that of the Cancer Medusarum, Otho Fabri- 
cius. Faun. Green., No. 232, in the number of joints of the legs, and in the 
four anterior being unarmed ; the conformation of these legs distinguishes 
it also from the Gammarus Medusarum of J. C. Fabricius, of which a part of 
the specific character is “ manibus quatuor monodactylis.’’ 
Crangon Boreas. 
Cancer Boreas, Phipps, Voy. App. 190, t. 12, f. 1. 
Several individuals were taken in the trawl on the west coast of Davis’ 
Strait, and in a dredge at Melville Island; in the minute, and otherwise 
very exact account which has been given of this species in the Appendix to 
Captain Phipps’s voyage, four strong spines were omitted to be noticed, 
situated beneath the thorax, one between each pair of legs, directed 
forward ; the anterior is the strongest, and they decrease successively in 
