NATURAL SCIENCES OF PHILADELPHIA. 101 



extensively in contact, tlie posterior smaller and separated from temporals by 

 four narrow plates, and from each other by fonr plates. The median pair of 

 the latter are the larger and join the anterior pair of infralabials. A groove 

 surrounds the throat behind the jaws, which is succeeded by five annuli of 

 equal ovate scales. These are followed by a cross series of six more elongate, 

 which precede a pair of large sternal plates extending between fore limbs. 

 Abdominal scales differeat from the dorsal, truncate, not hexagonal, in six 

 series. Dorsals in fourteen longitudinal, thiity-seven transverse rows between 

 nxilla and groin. Three elongate parallel anal plates ; a series of seven small 

 quadrate scales behind vent, each with a pore in the centre. Caudal scales 

 below, angulate like dorsal. 



Hind limbs style-like, minute, half as long as anal plates. Fore limbs as 

 long as three anterior labials, consisting of humerus, forearm and carpus, but 

 no digits ; three termiual tubercles are probably metacarpal. Tail very long, 

 subquadrate in section; the portion preserved, though nearly as long as the 

 body, presents no diminution of diameter ; the general form is probably snake- 

 like, as in Ophiosaurus. 



lu. Lin. 



Length head to rictus oris 2-25 



" " to gular fold 3-75 



" " to axilla G-5 



" " to groin 2 5 



" " to vent 2 6 25 



\Yidth head at angle mandible 2 



Color: below brown; sides with a brown blackish band, which is bounded 

 above by a rather narrow yellow band which commences on the superciliary 

 region. Dorsal region between the latter yellowish gray, bounded exteriorly 

 by a distinct blackish line, and divided medially by an indistinct blackish line. 

 The colors of the tail are similar. Head brownish, paler below. 



This species presents several points of resemblance to the Chalcides d o r- 

 bignyi Dum. Bibr. The specific differences, apart from the generic, may be 

 readily observed on comparing the descriptions. This is no doubt a sluggish 

 animal, and moves ranch in the manner of a snake. It is the most snake-like 

 of the Chalcididffi, approacliing somewhat the Amphisba^nia. 

 One spec, No. 6G37, from the Napo or Upper MaraQon. 



AMPHISBJENIA. 



Amphisb.kxa fcliginosa Linn. A. amcricana Sclireber, Gray. 

 Napo and Marauon. 



OPHIDIA. 

 SCOL ECOPHIDIA. 

 Typhlops reticclatus Linn. 

 Napo and Maranon. 



A&INEA. 

 Trachyboa gularis Peters, Monatsberichte Acad. Berlin, 18 , p. Emj'jrus^ 

 Jan. 



The character of the rostral shield appears to separate this genus from Eny- 

 grus, as Peters observes; the cranium is quite similar to that of Ungualia Gray. 

 From Guayaquil (No. 6G83.) 



Boa constrictor Linn. 



The loreal plate larger than the preocular ; two rows scales between orbit 

 and labials. No vertical or loreal brown band. 



Guaj^aquil. 



XiPHOsoMA HORTCLANUM Waglfcr. Boa Linn. 

 From Napo or Upper Amazon. (6679.) 



NiNiA ATRATA Cope. Coluher almtiis Hallowell, Strcpto2)horus drozii Dum. Bibr. 

 Elevated valley of Quito. 



1868. 



