^"Im''] PiJoci:i:niNGS of tiih national museum. 677 



This genus luis near allies ainonj;- the Dipsadine <;roup, to which it 

 belongs. From Dipsas it is distinguished by tlie divicb'd preanal phite; 

 from Ilimantodes* by tiie double scale pits, that genus having but one. 

 From Trimorphodou it difit'ers in the equality <)f the ntjgrooved maxil- 

 lary teeth and the single loreal plate. The greater numl)er of species 

 of this genus are Mexican and Central American, one specii's (.V. <innu- 

 /(//j<?/i) extending its range throughout tropical South AnuM-ica. One 

 species only has been found on the Kio Grande Uiver, and exten«ls 

 within our borders. The species are closely allied and are subject to 

 some variation. One only {8. rhombifcnDii (rthr.) I have not seen, and 1 

 give its characters on the authority of Giinther. All the species known 

 have but one temporal i)late in the first row. The species dilVer as 

 follows : 



I. Snporior labials eight toiiiiio. 

 a ScaU's in 21-.') rows. 



Body slender, compressed ; scales in twcnty-ono rows ; preocnlars two ; <lors.'il 



spots small, no postocnlar l);uul S. aitnulalum \ L. 



Body robust, cylindric ; Hcales in tweiity-ouo rows; preocnlars two; dorsal 

 spots large, wido; a conspicnons Idack postorbital baml. 



S. ifiicataiicnsei Cope. 

 Robust ; scales 2;!-.') rows ; preocnlars three ; conspicnons dorsal spots, and 



postorbital band S. sephiitrioiKilr Kenn. 



Kobnst ; scales twenty-one ; one preocnlar ; nnmerons transverse Idack dor- 

 sal rhombs, and no lateral spots ; to]) and sides of head black. 



.S. ])(rs('iintiim ji Coi>o. 

 Kobnst; scales twentj'-five ; loreal longer (ban deep; brown with yeUow 

 cross-bars and black-edged brown dorsal rhonil)s..5. rhombil'criim \\ (itlir. 

 Kobnst ; scales twenty-thren ; ])r('oenlars two ; loreal siinare ; black with nar- 

 row gray cross-bands; a conspicnons postocnlai- l»and : labials nine. 



iV. /rcMd/um!; Cope. 



•Ilimantodes Dnin., Bibr. Erp. Oen.. vii, V-^'il. ji. 1fln4. Tlie four species of this 

 genus may be distinguished as Ibllows: 



1. Two temporal plates in anterior row. 



A row of large vertebral scales ; very slender ; tail one-third If. rencoa L. 



A larger vertebral row : less slend(>r ; tail three and one-third limes in lengtli. 



If. Irucoinrliis Copo. 

 No larger vertebral row ; dorsal spots to gastrosteges ; slendi'r. 



//. l4 nuisniiiius Cope. 



2. One temporal scale of first row. 



No largo vertebral row ; le.ss slender //. (ininnittratuii Cope. 



//. ceHc/)Ort is South American ami extends norili to Vera Crnz ; the other specie 

 are Central American an<l Mexican. 



\ I.eptodini aniinhttit (Jthr., JMpstis ,iniiiil,it,i. D. and I?.: South Amoric.i. Paiiam!», 

 Costa Rica. 



\Sihoti anniilaliim iiucaianenae Cope, Proce«'ds. Acad. I'biia.. Htl^'i, p. 12T : Vnialan, 

 Belize. 



SS Leptodira persona la Co\M\ Tnx'. Acad. Bhila.. lH4;s, lUH. Mazatlan. Mexico, 



\\ Leptodira rhombifera Giiuther. Ann. M.agaz. Nat. Hist.. I'^2, a2. 



UProc. U. S. Nat. Miis.. 1"^H('., p. ISI. .lalapa. Me.\. 



