EXPLANATION OF PLATE IV 



Figure 14. — Orcliestia agilis Smith, (p. 555;) male; lateral view, eulai'ged five di- 

 ameters. 



15. — Gammarus ornatus Edwards, (p. 557 ;) male ; lateral view, enlarged two 

 diameters. 



16. — Amphithoe maculata Stimpson, (p. 563 ;) male ; lateral view, enlarged 

 two diameters. 



17. — Ampelisca sp., (p. 561 ;) lateral view, enlarged five diameters. 



18. — Cerapus rubricoruis Stimpson, (p. 565 ;) female ; lateral view, enlarged 

 five diameters; and hand of the second pair of legs of the male, en- 

 larged the same amonnt. 



19.— Unciola irrorata Say, (p. 567;) male; dorsal view, enlarged six diameters. 



(All tlie iigures were drawn by J. H. Emerton and S. I. Smith.) 



