266 Description of a Species of Caligus. 
. Fig. 3. A female, natural size 
. Fig. 4. a. View of the eadiaannters or second pair of legs, or maxillipeds; b, 
termination of third pair. 
Fig. 5. a. Ventral muscle, exhibiting its subdivision between the sternums of 
_ the two pairs of natatory legs; b, a second subdivision in the —- muscle, below 
the * pes of the above sternums. 
Fig. 6. a and b. View of the posterior thoracic joint, (see fig. 7,) with es date 
in the circulation ; the two lateral valves on the back and the central on the 
Prats IV. 
Fig. 7. Back view of a male, with the muscles seen in this view. Those mark- 
ed with capital letters, move the segments of the body; those with small letters, 
move the several organsbelow. F, be posterior thoracic segment; G, the anterior 
peeery H, the posterior abdom 
. 8. A portion of the shell a the = shewing the areolets exhibited by 
it; < pobeates line marks the limits of the dark ground on which the eyes are s! sit- 
ted, d circles the eyes Hiedienives 
Fig. 9. Siabibriary canal, exhibiting the esophagus, the stomach and the intes- 
tine, with its glands, and the muscles of the rectum. The mouth at the upper ex- 
tremity is represented as turned back, so as to show its under surface. 
Fig. 11. A portion of the intestine. 
Fig. 12. View of the mass, in its natural position. Between the linea a, 
and aba, is the opening to the mouth. d, the outer extremity of the mandibles, 
with the tendon and its muscles attached. 
. The same with a portion of the upper membrane and the mandibles re- 
moved. 
Fig. 14. The ae together with some of the organs adjacent to their in- 
ner extremities, showing their relative on. 
stad 15. The upper lips, with its two a of muscles. 
Fig The same, with the extremity retracted by the inner pair of muscles. 
Fig. 17. Under view of the buccal mass, with the esophagus attached. h h are 
processes lying in the teguments of the body, with which the buccal mass forms an 
articulation at their anterior extremity. g the processes in which the elevators of 
mass are inserted. 
Prats V. 
Fig. 18. Under view of female, exhibiting the nervous sys tem, and the ovaries, 
and ovarian tubes. Fig. 18, a, the first pair of maxillipeds in the female; 18, b, the 
fourth pair in the same. 
Fig. 19. A view of the cup and an antenna, together with a portion of the lat- 
eral margin of the animal, exhibiting its spines. The dotted lines in the antenna 
represent the nerve with which this organ is largely supplied 
Fig. 20. The cephalic and thoracic ganglions, exhibiting their close union, and 
the nerves they give out; the outlined organ in front, represents the eyes, @ attached 
to the ophthalmic nerves. 
Fig. 21. Genital system in the male. 
Fig. 22. Part of the abdomen of a female with an appendage to the same. 
ae 23, 24, 25. Illustrate some facts connected with the change of skin. 
