35. IGUANA. 191 
I regard this form as merely a variety of the preceding, the only 
difference being the development of two or three of the median 
scales of the snout, behind the line of the nostrils, into conical, soft 
tubercles. In adult males these tubercles are more developed and 
form a small crest, but in some females the crest is quite indistinct, 
and the young are not always to be surely distinguished from 
I. tuberculata. I must also observe that some of the specimens 
(t, s, ¢) which I have referred to the latter show clearly in the 
scaling of the snout a tendency towards the rhinolopha form, 
so that there is a gradual passage from the one to the other. 
The other character which has been given as diagnostic, viz. the 
number of scales in the dorsal crest (from its origin on the nape to 
the base of the tail), is hardly of importance. Although there is 
usually a lesser number of these scales in I. rhinolopha than in 
I. tuberculata, this distinction is not a reliable one: our series of 
specimens show variation between 47 and 66 scales in the latter 
form and between 44 and 58 in the former; and it is remarkable 
that the specimens of J. tuberculata with subconical scales on the 
snout give the highest numbers (62 to 66), whereas the specimen 
of I. rhinolopha in which the rostral tubercles are the least de- 
veloped has, on the contrary, the smallest number (44). 
Central America and West Indies. 
a. Ad., stuffed. St. Lucia, W. Indies. 
b. Ad., stuffed. Central America. O, Salvin, Esq. [C.]. 
ce. Yg. Central America. Haslar Collection. 
d. Ad., stuffed. Mexico. 
e. Yg. Mexico. 
f. 3 Cordova, Mexico. 
g, h. ‘Ad, skins. Cozumel Island, Yucatan. F. D. Godman and O. 
Salvin, Esqs. [P.]. 
a Ye. Honduras. : 
k-l. Ugr. Mazatlan. Hy. A. Forrer fe: ; 
m,n,o. Ad., skins. Presidio. Hr. A. Forrer [C.]. 
p. &. Chiapas. O. Salvin, Esq. (C.]. 
q 3. Pacific coast of C. America. A. Vidler, Esq. [P. |. 
r. Yg. Pacific coast of Guatemala, O. Salvin, Esq. [C.]. 
8. Q. Panama. 
9. 
2. Iguana delicatissima. 
Iguana delicatissima, Gray, Cat. p. 187. 
Iguana delicatissima, Laur. Syn. Rept. p. 48. 
—— nudicollis, Cuv. R. A. 2nd ed. ii. p.45; Guér. Icon. R. A., Rept. 
pl. xi. fig. 1; Dum. § Bibr. iv. p. 208; Cope, Proc. Am, Phil. Soc. 
1869, p. 159. 
Amblyrhynchus delicatissimus, Wagl. Syst. Amph. p. 148. 
Differs from J. tuberculata in the following points :—Scales on the 
occiput more or less conical ; no large shields below the tympanum, 
but a regular series of large chin-shields, parallel with and much 
larger than the labials, on each side; only a few triangular com- 
