476 REPORT OF NATIONAL MUSEUM, 1898. 



The two aorta roots extend considerably anterior to tbe heart before 

 turning posteriorly ; the right root receives near its origin the common 

 carotid, which soon thereafter divides into the right and left carotid. 

 The right and left bronchi are distinct, but not elongate. The lungs 

 are of subequal length; they are filled with coarse cells for about two- 

 thirds their length. 



The liver extends cephalad to the heart by its left lobe, the right 

 falling a little short. The entire organ is large and elongate, the right 

 lobe extending considerably beyond the left, but not terminating in a 

 narrow strip, as in many Pachyglossa. The gall-bladder looks down- 

 ward through a round foramen of the liver, between its two distal 

 lobes, which are joined candad to it. The alimentary canal includes an 

 elongate stomach, followed by a rather elongate small intestine, which 

 passes gradually into a moderately large rectum. The muscular walls 

 of the stomach are not thick. The kidneys are rather wide, and about 

 two-thirds of their length is within the pelvic cavity, the remaining 

 third projecting anteriorly to it. 



The hemipenis is undivided. Opposite to the sulcus spermaticus is 

 a welt, which is smooth ; between it and the sulcus are coarse plicate 

 transverse folds, which extend to the apex of the organ. 



There are two species of this genus, which differ as follows: 



Pterygo- palatine teeth present ; tail equal or longer than body ; head and neck about 

 half body; fore limbs to orbit; predominating color, black H. liorridnm. 



No pterygo-palatine teeth ; tail two-thirds body ; bead and neck one-third body ; fore 

 limb to orbit ; predominating color, yellow H. suspectum. 



The Heloderma horridum Wiegmann has been brought from western 

 Mexico, from Presidio on the north to as far south as the Isthmus of 

 Tehuantepec. It has not been brought from eastern Mexico, so far as 

 I am aware. The H. suspectum Cope is restricted to southern Arizona 

 and New Mexico, so that a wide interval intervenes between the ranges 

 of the two species. 



HELODERMA SUSPECTUM Cope. 



Heloderma suspectum Cope, Proc. Acad. Nat. Sci. Phila., 1869, p. 5. — Boulen- 



GER, Cat. Liz. Brit. Mus., 2d ed., II, 1885, p. ?>m. 

 Heloderma horridum Baird, U. S. Mex. Bound. Surv., II, Eept., 1859, pi. xxvi, 



not of Wiegmann. — Cope, Proc. Acad. Nat. Sci. Phila., 1866, p. 303. — 



BocouRT, Miss. Sci. au. Mex., 1878, p. 297, pi. xxE, figs. 1-12; pi. xxG, 



figs. 1, 3, 6, 7, 8, 9, 10, 11. 



Head about one-fifth the head and body; its width four-fifths the 

 length. Tail about half the head and body. Hind legs contained three 

 and one-half times in head and body; from the knee a little more than 

 four times; this distance less than from elbow to end of claws. A shal- 

 low groove along median dorsal region of back and tail, with indica- 

 tion of another beneath. 



General color purplish brown or black, varied with about eight rings 

 of yellow, changing behind to orange. These are about two-thirds the 



