EXPLANATION OF PLATE X. 
FicurReE 40.—Lepidonotus squamatus, (p.581;) anterior part of the body, head, and 
proboscis; dorsal view. 
41.—The same; end of the proboscis; front view, showing the jaws and 
papille. 
42.—Lepidonotus sublevis, (p. 581;) dorsal view. 
43.—Rhynchobolus dibranchiatus, (p. 596;) anterior part of body, mouth and 
head ; lower side. 
44.—The same; lateral appendage, showing the dorsal cirrus, the upper and 
lower branchie and the setigerous lobes between them. 
45.—Rhynchobolus Americanus, (p, 596;) anterior part of the body and ex- 
tended proboscis; dorsal view. 
46.—The same; lateral appendages, showing the dorsal cirrus, the branched 
gill, the setigerous lobes, and the ventral cirrus. 
(Figures 40, 41, 42, 45, were drawn from nature by J. H. Emerton; 44 by A. E. Verrill; 43 and 46 
were copied from Ehlers.) : 
