CROCOUILIANS, LIZARDS, AND SNAKES. 883 



of tlie principle, Avliich I have elsewhere insisted on, ''that adjacent species of allied 

 genera may bo more alike than remote species of identical generic characters," which 

 indicates that generic characters originate independently of the specific. 



The transitions above noted are not, however, without mutual corre- 

 lations. The chaiaeters are found so associated in such a great major- 

 ity of the specimens as to indicate the existence of subspecies whose 

 definitions are given below. Exceptions to these are given under the 

 head of each subspecies. 



I. No yellow band posteriorly from orbit (a yellow half collar). 



(X. Dorsal spots or saddles (red) open at the side, their adjacent borders forming 

 pairs of black rings. 

 Interspaces between red saddles open below ; scales not black tipped ; front 



black ; first black ring on nape only O. d. coccinea. 



Interspaces betAveeu red saddles closed by black spot below ; scales black 



tipped ; front black ; first black ring complete O. d. •pohjzona. 



Interspaces not closed ; rings, including first, complete on belly ; first yel- 

 low baud crossing occipital plates; front black; scales not black 



tipped 0. d. occipitalis. 



aa Dorsal saddle spots closed at the sides. 



(5 Saddles closed by a single black tract on the middle of the belly ; no spots 

 between saddles. 

 Dorsal spots undivided medially ; front black ; first black ring complete. 



0. d. annulata. 

 Dorsal spots divided longitudinally by a median black connection ; front 



black 0. d. (jentilis, 



/3/3 Lateral borders of saddles not confluent with each other below. 



Saddles completed on gastrosteges ; no alternating spots; no black 



collar 0. d. paraUela. 



Saddles completed oij gastrosteges ; siiots opposite intervals forming a 



single series on the middle line of the belly O. d. sysjrila. 



Saddles completed above the gastrosteges; alternating spots which do 

 not meet on the middle lino of the belly O. d. doliata. 



II. A yellow baud from orbit bounded below by a black or brown one. (Saddle 



spots closed laterally above gastrosteges ; superciliary light spots or 



bands.) 

 A half collar touching occipital plates, no bands; alternate spots largely on 



gastrosteges 0. d. coUaris. 



Neck with longitudinal bands; alternate spots largely on gastrosteges. 



0. d. clcrica. 

 Neck with bands; alternate spots entirely on scales O. d. triangula. 



The more detailed transition from the simple head coloration of the 

 0. d. coccinea to the complex pattern of the 0. d. triangula is accom- 

 plished as follows : 



A yellowish spot is seen on the superciliary plate of the single si)eci- 

 men of the 0. d. paraUela known, and on three of the fifteen specimens 

 of the 0. d. sijspUa. It appears in all of the thirteen 0. d. doliata, and 

 in two of these they nearly join across the front, and in three they join 

 forming a cross band. In four specimens of the 0. d. doliata a notch 

 of the black anterior border of the nuchal collar appears on each side. 

 The depressing of this notch till it reaches the eye defines the two post- 

 ocular stripes of the subspecies of Section II of the preceding table. 



