EXPLANATION OF PLATE XIII. 
Fictre 65.—Autolytus cornutus, (p. 590;) an asexual individual, from which a male is 
about to separate; dorsal view, enlarged about six diameters; A, A, A, 
antenme of the former; C,C,C, C, two tentacles and one tentacular 
cirrus on each side, followed by the dorsal-cirri; F, the intestine; d, the 
long sete and dorsal cirri of the male, 
66.—The same; anterior part of a female, more enlarged ; the letters as before ; 5 
b, the eyes; ¢, the eggs; f, the intestine; 3, one of the appendages of 
the anterior region of the body; ¢, the dorsal cirrus; h, the setigerous 
_ tubercle, supporting hooked setx. 
67.—Diopatra cuprea, (p. 593 ;) head and anterior part of body, showing part 
of the branchie ; side view. 
68.—The same; ventral view, showing the mouth open and jaws thrown back. 
69.—Lumbriconereis opalina, (p. 594 ;) anterior part of body; dorsal view. 
70.—The same; lateral appendage and sete. 2 
(Figures 65 and 66 were copied from A. Agassiz; 67, 68,69 were drawn from nature by J. H. Emer- 
ton; 70, by A. E. Verrill.) 
