Peracarida — Tcinaidcicea , Isopoda. 41 
The Tanaidacea, which are all marine, and generally of very Table-case 
small size, are of great interest as preserving, along with the No ‘ 6 ‘ 
Cnmacea, links of connection between the stalk-eyed or “ pod- 
ophthalmate ” type of the Mysidacea and the sessile-eyed or 
“ edriophthalmate ” Isopoda and Amphipoda. 
Order 4.— Isopoda. 
There is no distinct carapace. As a rule, only the first 
thoracic somite is fused with the head, and the other seven are 
Fig. 22. 
Bathynomus giganteus, about one-half natural size. (From Lankester’s 
“ Treatise on Zoology,” after Milne-Edwards and Bouvier.) [Table-case 
No. 6.] 
free. There are no exopodites on the thoracic limbs. The eyes, 
when present, are sessile. The body is usually flattened from 
above downwards. The abdominal appendages are lamellar and 
respiratory. 
