OF THE AMERICAN KING-CRAB. 479 
the nippers of the anterior pair of feet (11), aided, if necessary, by those of some of the 
others. The manducatory limbs then begin an alternating motion of their haunches 
upon the food, by drawing one of those rasp-like joints against the opposite one of the 
same pair, the food being held between the two. This chewing by means of these 
opposing rasps reminded me," writes Dr. Lockwood, “of the hand carding-process, in 
which the card held by the right hand is brought towards and against the one held in 
the left hand, the wool being between, when the right hand card is held still, and the 
left hand duplicates the motion, and so on. The fine particles rasped off by the incurved 
teeth pass into the mouth ” *, | 
The tumid and wrinkled margins of the mouth quickly contract to an cesophagus about 
a line in diameter. This tube (Pl. XXXVII. fig. 2, e) curves upward and forward in a 
course of 1} inch; then dilates into a conical proventricular cavity (r) extending down- 
ward, about 5 lines in depth by 3j in breadth at the base. From the fore part of the 
base a second short canal ascends, to terminate by a slight vascular prominence in the 
stomach (s). The epithelium, or modified chitine, continued from the mouth along the 
gullet and proventriculus, becomes suddenly thickened in the stomach, and is disposed in 
numerous transverse ridges, The museular coat of the stomach is concomitantly 
strengthened, attaining at one part a thickness of 3 lines. The pyloric end (mt) projects 
as a truncated cone, 4 or 5 lines long, into the dilated beginning of the intestine (7). The 
truncate apex of the pylorie cone is slightly tumid. "The epithelium lining that part has 
resumed its thinness and subtransparency. 
The intestinal tunies appear to be reflected from the base of the pylorie cone; they 
define a dilated beginning of the canal, and gain a slight thickness of the muscular coat 
as they contract to the common size of the intestinal tube, the area of which is about 
5 lines in transverse, and 3 lines in vertical diameter. The tube goes nearly straight to 
the vent (Pl. XXXVII. fig. 1, 2, v); but, about halfway there, it contracts transversely 
(Pl. XXXVI. fig. 1, 2), and exchanges its oval for a circular section, with a diameter of 
3 lines. Near the vent it again expands, chiefly transversely; and the muscular coat 
there gains somewhat in thickness. The vent (Pl. XXXVII. fig. 1, v) is a transverse 
slit with tumid margins, just anterior to the joint between the thoracetron and pleon. 
The contents of the alimentary canal were pulpy and scanty. The principal food of 
the Limulus polyphemus is stated by Dr. Lockwood (loc. cit.) to be Nereids, routed by 
the cephaletral limbs out of the mud or sand displaced in the act of burrowing. 
The only gland in communication with this canal is the liver. It is of great size; its 
minute terminal acini are compactly massed together, and occupy most of the space in 
the cephaletron not given to other organs, mainly the generative, the ramifications of 
which interlace with the hepatic lobes. A part of this mass is shown at z, fig. 1, Pl. 
XXXVI.; but it extends forward to the space anterior to the stomach, and backward 
by a narrow tract (ib. 2') on each side of the intestine in the thoracetron. The lobes, or 
larger groups of acini, form a close-packed series on each side, corresponding in the main 
in number with the apodemal spaces and the epimeral nerves. The least unsuccessful 
trials of injecting the terminal canals and acini indicated the greater transverse and less 
; * Lockwood (Rev. S., Ph.D.), in * The American Naturalist,’ vol. iv. p. 260 (1870). 
