764 EXPLANATION OF PLATES. 



angular bone; u, dental bone, dentary Ow. The other letters 

 correspond with the same in fig. 12. 



Fig. 14. Right half of the lower jaw of Iguana delicatissima (Iguana 

 nudicollis), p. 305. The attachment of the teeth to the inside 

 of the margin of the jaw is seen, p. 298 ; z, os complementarium, 

 and 05 operculare; the other letters correspond to those of 

 fig. 13. 



PLATE Y. REPTILES. Continuation and conclusion. 



Fig. 1. Head of Ccecilia hypocyanea from a young individual. Behind 

 the eye the branchial aperture * is seen, p. 238. 



Fig. 2. Anterior portion of Hypochthon xanthostictus FITZ., p. 241 ; 

 in front of the three-toed fore leg the large branchial tufts are 



seen. 



Fig. 3. Anterior portion of Amphiuma tridactylum, p. 241. 



Fig. 4. Full grown embryos of Salamandra atra, p. 242. A, such 



an embryo stretched out; B, an embryo folded, as it lies in 



the oviduct of the parent. 



Figs. 5, 6, 7. Head of Homalopsis angulata, p. 268. Fig. 5 from the 

 side; fig. 6 from above; fig. 7 head of another specimen of the 

 same species from below : to explain the nomenclature of the 

 scutes in the heads of serpents (see the note, p. 262), used by 

 MERREM (Sy sterna Amphibiorum Prsefat. xn, xm) : 



a, Scutum vertebrale (scuta vertebralia). 



b, b. Scuta occipitalia. 



c, c. Scuta super ciliaria. 



d, Scuta temporalia. 



e, e. Scuta frontalia posterior a. 



f. Scuta frontalia anteriora (only a single scutum in the 

 figure drawn by us). 



g. Scutum rostrale. 



h. Scuta ocularia posteriora. 



i. Scuta ocularia anteriora (scutum oculare anterius). 



k. Scuta lorea. 



m. Scuta marginalia labii superioris. 



n. Scutum labiale medium (Fig. 7 N). 



o. Scuta labialia accessoria (Fig. 7 o, o). 



q. Scuta mentalia (Fig. 7 Q, Q). 



r, r, r, r. Scuta marginalia labii inferioris (Fig. 7 R, R). 



