Peracarida — A mphipoda. 
45 
shows the parasite in situ in the shell of the crab. The yellow 
mass is the greatly developed brood-pouch, which is distended 
with eggs. The figure on the left represents a younger specimen 
removed from the crab and. further enlarged. The flaps of the 
empty brood-pouch have been turned back. 
Order 5. — Amphipoda. 
As regards the segmentation of the body, the sessile eyes, and 
some other characters, the members of this Order agree with the 
Gammarus locusta, male, from the side, enlarged, a', antennule ; a", antenna ; 
acc, accessory (inner) flagellum of antennule ; br, gill-plate ; cx, coxal 
plate (the expanded first segment of the leg; gn, the two pairs of “ gnatho- 
pods ” (prehensile legs) ; pip'", abdominal appendage of third pair ; prp', 
prp", first and second peraeopods or walking-legs ; t, telson ; ur, uropod ; 
II., VIII., second and eighth thoracic somites ; 1,6, first and sixth 
abdomina lsomites. (From Lankester’s “ Treatise on Zoology,” after Sars.) 
Isopoda, but the body is usually compressed from side to side, the 
abdominal appendages are not respiratory, and there are gill- 
plates attached on the inner side of the bases of some of the 
thoracic limbs. 
The Amphipoda are grouped under three Sub-orders. 
In the Sub-order Gammaridea are included the typical Amphi- 
poda, in which the body is more or less stout, the abdomen well 
developed, and the eyes generally small. The most familiar 
members of this Sub-order are perhaps the Sandhopper, Talitrus 
saltator, and the Shorehopper, Orchestia gammarellus. These two 
Table-case 
No. 6. 
Table-case 
No. 7. 
