106 PROCEEDINGS OF THE ACADEMY OF 



with the cylindric body and clonofate tail of Bascanium. The relative length 

 of tail, within the proportions included by the genera in question, is, however, 

 a more variable character than the integrity of the anal plate as a generic 

 feature in our estimation. I therefore refer it to the Spilotes series. The 

 divided anal plate is also characteristic of Masticophis, (Peters describes a 

 Mexican species in which he says it is variable) ; this species is, however, more 

 massive than these, and generally proportioned as the Bascanium constric- 

 tor. 



Scales in fifteen rows, broad, subequal, all smooth. Tail 3-6 times into the 

 total length. Head rather distinct, ovate, muzzle not prolonged. Anterior 

 margin four-fifths total length ; lateral margins slightly concave. Prefrontals 

 broader than long. Occipitals concavely, continuously truncate behind ; tem- 

 porals 2 I 2, entirely in contact with two last labials. Only one small plate be- 

 sides bounding occipital. Superior labials eight, fourth and fifth bounding 

 orbit; sixth subtriangular, in contact with lower postocular. Postnasal higher 

 than prenasal, loreal higher than long, one pre- two short postoculars. Inferior 

 labials nine ; postgenials considerably longer than the pregenials. The ros- 

 tral plate is rather narrowed and with concave sides ; it is barely visible from 

 above. 



Above and gastrosteges to one-fourth their length on each side, deep black. 

 Lower surfaces, with upper labial shields, yellow ; black margin dividing two 

 last labials horizontally; no dark margins to labials. 



Total length 51 in. 8 lin. ; of tail 13 in. 81. Gastrosteges 169 ; anal 1; 

 urosteges 92. 



This fine species is from the Napo or Upper Maranon. No. 6660. 



To this genus must be referred the Geoptr/ns collans and G. flavivcntris Stein- 

 dachner (Sitzungsber. Wien, 1867, 271), while the name Geoptyas applied to 

 Coryphodon p a u t h e r i n u s and C. constrictor of the Erp. Generale must 

 become a synonym of Bascanium, Baird and Girard. G. collaris is Sp. ra e 1 a- 

 n u r u s, from Mexico, while the G. flaviventris is too near Sp. c o rais. 



Thrasops CUPREU3 Cope, sp. nov. 



A slender, cylindric species, with an unusually short broad head. 



Scales in fifteen longitudinal rows, the three median a little larger than the 

 others and equal, the median five, keeled, the keels invisible or nearly so, when 

 the epidermis is lost. Head flat above, muzzle contracted and short. Rostral 

 plate little visible from above, much broader than high, internasals subtrian- 

 gular, behind broad as long. Prefrontal on one side descending to labials, on 

 the other, all below the canthus roslralis cut off as a large loreal. Frontal 

 not longer than supercilaries, with concave sides and a right angle behind. 

 Occipitals well developed, broad, broadl^^ truncate behind, bounded by five 

 temporals. The anterior of these is much the largest and in contact with 

 three labials and the postoculars ; behind it a second large plate borders the 

 last labial only. Superior labials eight, none elevated, fourth and fifth mar- 

 gining orbit ; oculars one, two, the inferior posterior minute. The long narrow 

 nasal is acuminate posteriorly, and borders the first and half the second labial, 

 and the internasal plate exactly. 



The number (15) of rows of scales is retained on the neck. Total length 

 20-5 in.; of tail 8 in.; of gape of mouth, 5-5 lines. Gastrosteges 152, anal 

 divided (generic char.) ; urosteges 136. 



Color above metalic copper color, with the shades at the bases of the scales, 

 and cross-shades of the same on the anterior half of the body. A narrow 

 dark streak from nasal plate along upper edges of labials ; the latter and chin 

 yellowish white, below brown copper colored, with darker dashes. When the 

 epidermis is lost, which very readily occurs, the derm appears of a coppery 

 silver color. 



From the Napo and Maranou. No. 66G6. 



[March, 



