MYSIS. 
141 
Boothia depend in a great measure for their winter store of 
provisions. It is also the chief food of the whale, by which 
such a prodigious quantity of fat is produced in the body of 
that immense animal. During the summer they assemble 
in vast myriads at the mouths of rivers, but in the winter 
they are more generally distributed along the whole line of 
coast, and, together with the Argonauta arctica , are to be 
seen in every crack that opens with the tide, even at the 
coldest period of the year.” 
Bam. MYSIDIDAE, M. Edw. Opossum Shkimps. 
All the legs of the same form, and fitted for swimming. 
Thorax thick and compressed on the sides. Carapace with 
the margins folded under at the base of the legs, and 
nearly concealing all the thoracic ring. Abdomen much 
developed ; there are six or eight pairs of thoracic legs, 
which are provided with a well- developed palpus, which 
makes them appear double. 
Gen. 48. MYSIS, Latr. — (Plate IX. fig. 4.) 
No thoracic branchise. One or tw 7 o pairs of foot-jaws ; 
hind feet complete. False abdominal feet very small, and 
without branchial appendages, the last two feet furnished 
