EXPLANATION OF PLATE X. 



FiGUKE 40. — Lepidonotus squamatns, (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 

 l^apillse. 



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 branchisB 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.) 



