vol 



iyi;' ] PROCEEDINGS OF TIIK NATIONAL MUSEUM. 673 



Natrix fasciata eiythrogaster Sli;i\v. 



Cope, I'lDc. K. S. N;it. Mas., l.S-8, p. :VJ^. 



Coluber erijthrogaslcr Shaw, Gon. Zoiil., iii, 1802, p. 4'>8; Ilolbrook, N. Aiikt. Mcrp . 

 II, 1838, p. 91, PI. XIX. 



T*oj)ir/o«o/(j.'j fn/^/fjOf/rtS/t-r Ilolbr., N. Aiucr. Hcrit., 2(1 0(]., Ill, l84'-i, \>. s:,, I'l. \ui; 



Diim. 15ibr. Kip. (Jiii., vii, IH.^4, p. f)?!). 

 Nerodia erijthvogaxli r ]>il. ami Gird., Cat. Serpt. N. Amor., 185:5, p. 40. 

 Tropidonotui sipcdoii crythroijaslcr Cope, Check List Batr. Rept. N. .Viner., 1875. 



Austroiipariun region, entering rarely the eastern. 



Natrix iliombifera Hallow. 



Troiiidonot IIS rhomhif crWiiWowcW, Proc. Acad. Pliila., IM.VJ, ]>. 177; Cope, Cimck List 

 N. Amer. ]}ati-. Rept. 1H75, p. 43; .ATerof/irt W(OH(&i/<T lid. and (Jird., Cat. Re)>t. 

 Sorp'i., \^7^.^, p. 147; Xerodia holbrookii \\A. ami (linl., 1. c, p. 43. 



Tropidoiiotiis poiiouiuH Diiui. liibr., Krp. tieii., 1834, i>. 574. 



TropidoiiolusfiiHciatiis var. pogonias Jim, Icon. Gen. Olid, ii, '.i(>. iii, Vi^. 1. 



Tropidonotns cijcloinon Jan, Icon. Gen. Olid, ii, 'i\\, vi V'\'^. 1, not oil), ami B. 



In thirteen specimens in which I counted tiie rows of scaU's, I found 

 but one in which the nuinUer is not twenty seven ; this was in No. 

 10751>, asinall and starved individual, which ha.s twenty-live row.s. in 

 dimensions this water snake rather exceeds the A', h. fiiHciatux^ and is 

 only exceeded in our fauna by the y. taxispUota. 



The Lower Mississippi is the headquarters of this species, where it is 



very abuiulant. It is not yet known from east of tliat river, but 



ranges north to the limits of the Kegio Austroriparia, to southern 



Illinois, and west throuo-hoiit Texas. It is the only one of our water 



snakes which extends to the Ticrra Caliente of Mexico, having been 



brought by the Commission Kx[)loradora from Misantla, in the State 



of \'era Cruz. 



Natrix cyclopiuni Dnni. Hibron. 



Tropidonotns cijclopiinn DiinK^ril A Bibron, Erpetoiogie Gf^ni'rale vii, p. .'i7r>; (iiiiither, 

 Cat. Col. Snakes Brit. Mu.s., 18.")8, p. 77; Cope, Proc. Acad. Pliila., 1H«)1. p. 

 •21H); Check List N. Ainer. Batr. Rept., 187.">, p. 43. 



This well-marked si)ecies is much less abundant than its allu's tlu" 

 N. rhoinhi/cra and X. t(U'ispilo(((. The few specimens in the Niitional 

 Museum collection come from the three extreme points of tlie .Viistro- 

 riparian district, viz, Florida, New Orleans, and south Illinois. 



The^V. cyclopium is nearest the N. rhombifcr. The pattern of colora- 

 tion is quite dillerent: and the scutellation also dilVers in sevenil im- 

 portant respects. In ihe .V. cyclopium the nasal phites arc shorter an- 

 teroposteriorly, and there are only two .scuta whicli are properly postoc- 

 ular. The posterior tem|)L)rals are smoother, ami not keeled, ;ind the 

 body scales are emarginate, which they are not in the .V. rhomhi/cru. 



The possession of a series of scales below the oritil, wliile present in 

 all known specimens of this species, is not confined to it. I liave.seen 

 it in a specimen of the X. ta.vispilota, ami it is found in the only known 

 specimen of the Xatri.v anoscopus* Cope, from (juba. 



■ I'ropidonotus anoscopua Cope, Proc. Acail. Phila., 1861, p. iii>".>. 



i'loc. N. :m. *»1 43 



