EXPLANATION OF PLATE IY. : 
FicureE 14.—Orchestia agilis Smith, (p. 555;) male; lateral view, enlarged five di- 
ameters. 
15.—Gammarus ornatus Edwards, (p. 557 ;) male; lateral view, enlarged two 
diameters. 
16.—Amphithoé maculata Stimpson, (p. 563;) male; lateral view, enlarged 
two diameters. 
17.—Ampelisca sp., (p. 561;) lateral view, enlarged five diameters. 
18.—Cerapus rubricornis Stimpson, (p. 565;) female; lateral view, enlarged 
five diameters; and hand of the second pair of legs of the male, en- 
larged the same amount. 
19.— Unciola irrorata Say, (p. 567;) male; dorsal view, enlarged six diameters. 
(All the figures were drawn by J. H. Emerton and S$. I. Smith.) 
