Mi PROCEEDINGS OP THE ACADEMY OP 



angle of the vertical shield is one line greater than that anterior. Side of the 

 head constricted at the orbits, the muzzle rather narrow and truncate. Ros- 

 tral plate broader than high, with but four sutural borders, the superior very 

 long ; the apex apparent upon the surface of the head. Prefrontals much 

 broader than long ; one -third the size of that part of the postfrontals visible 

 from above. Upon a vertical view, the postfrontals appear longer than broad. 

 Occipitals, superciliaries and vertical developed ; the last presenting a right 

 angle posteriorly, and having the lateral borders slightly concave and converg- 

 ing ; the first not longer, and about as wide as long, in contact with a large 

 scale in their posterior, common emargination. Nasal plates distinctly di- 

 vided, very small, higher than long. Loreal plates two, the anterior higher 

 than long, intercalated superiorly between the pre- and postfrontal, posterior 

 as long as high. Preoculars three, the superior largest, not in contact with 

 the vertical ; the inferior bounded anteriorly by the third upper labial. Post- 

 oculars three, the inferior a little the largest. Superior labials nine, fourth 

 and fifth entering the orbit, sixth largest, higher than broad. Inferior labials 

 twelve, the third and fourth narrow, and much produced posteriorly. Gene- 

 ials two pair, the anterior longest. Gastrosteges 236, one divided anal, uros- 

 teges 70. Total length 27 in. 10 lin. Tail 4 in. 4 lin. 



Coloration. The ground color is a light grey. The muzzle is crossed by an 

 indistinct ashy band, which extends upon the anterior part of the postfrontals. 

 The posterior half of these plates is involved in a deep brown band which 

 crosses the head between the eyes, whose posterior border is very concave, 

 extending upon the superciliaries to the vertical plane of the pupil of the eye. 

 This band is continued posteriorly, upon the inferior postocular and sixth 

 upper labial. A pair of broad diverging bands commences one band on either 

 side of the centre of the vertical, crosses the superciliary and occipital shields, 

 and following the expanded outline of the temporal and tympanic regions, 

 contracts and becomes longitudinal and parallel upon the neck. A brown 

 spot upon the posterior extremity of the vertical plates with a posterior 

 elongation, completes the resemblance of this figure to a lyre, or still more to 

 that musical (?) instrument familiarly known to children as the " Jews-harp." 

 The ground color appears upon the vertex as an anchor-shaped figure, and on the 

 cheek, as an oblique band. The back, as far as the anus, is ornamented with 

 twenty- one pairs of deep brown spots, their gemination only apparent anteri- 

 orly by the punctulate character of the scales in the intervals between the 

 pairs. These intervals are always about three scales wide ; the lesser, two 

 and a half anteriorly, one and a half posteriorly. Dorsal spots seven scales 

 wide; as the scales are broader posteriorly, the spots are also. There is 

 an irregular series of lateral spots, one opposite each of the intervals, some- 

 times confluent with the dorsal spots : anteriorly they form a very narrow 

 broken band. Another series of spots involves the tips of pairs of the gastro- 

 steges, which are separated by two, three, four, or even five immaculate ones. 

 Ten confluent pairs of spots on the upper surface of the tail. Whole under 

 surface whitish. 



Type (Sm. No. 4080), discovered by Mr. J. Xantus at Cape St. Lucas, Lower 

 California. Another specimen collected by Mr. Irwin, at Ft. Buchanan, Ari- 

 zona, appears to be identical, though in a bad state of preservation. 



The discovery of this species by Messrs. Irwin and Xantus, is one of the 

 most interesting additions to North American Herpetology. The form is 

 strictly tropical, for we learn from the Erpetologie Generale that the L. gem- 

 i n a t u s is Brazilian, and the scolopax has been brought from Guiana and 

 Santa Cruz de la Sierra in the eastern region of Bolivia. There are no other 

 species known. It is important to notice that the present species differs from 

 those of South America in the possession of two loreals and three preoculars, 

 but with our present knowledge of the Dipsadinae, generic difference can 

 hardly be predicated upon peculiarities of this kind. 



[Aug. 



