EXPLANATION OF PLATE XI. 
Figure 47.—Nereis virens, (p. 590;) head little more than natural size ; dorsal view. 
48.—The same; extended proboscis; dorsal view. 
49.—The same; probosci; sventral view. 
50.—The same; lateral appendage. 
51.—Nereis limbata, male, (p.590;) a few segments of the middle region of the 
body, anterior region, head and extended proboscis ; dorsal view. 
52.—Nereis pelagica, female, (p. 591;) natural size; dorsal view. 
53.—The same; male, natural size; dorsal view. 
54.—The same; head more enlarged; dorsal view. 
55.—The same; proboscis; ventral view. 
56.—Phyllodoce gracilis?, (p. 586;) head ; dorsal view. 
(Figure 51 was drawn from nature by J. H. Emerton; 47, 48, 49, 50, 52, 53, were copied from Ehlers; 
34, 55, from Malmgren; 56, from A. Agassiz.) 
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