178 MAJOR F. WALL, I.M.S., O.M.Z.S. 



notes I use the following formula: In fig. 28, L/ab. 8 ; 12 (f 4 ■§■) f , the bracketted 

 figures implying contact with the eye. To take another example of the tendency 

 to variation in these shields see figure 66. Here these shields are 9, the an- 

 terior 7 entire, the fourth, fifth and sixth touching the eye. In figure 67B 

 representing the same species, the third, fourth, fifth and sixth shields are 

 divided, the upper portions of the fourth and fifth being confluent. I would use the 

 formula 10, I2f ( f f f } f), and in so doing imply that three labials touch the eye, though 

 in reality only two do so. It seems to me the only reasonable way of recording it. 

 Unfortunately many herpetologists have taken a different view, and on the strength 

 of their view created new species on grounds to my mind quite unjustifiable. To take 

 a good case as illustration see figures 39 and 40. Mr. Boulenger presumably on the 

 assumption that the posterior maxillary teeth in nigrocinda are not grooved (though 

 this is a mistake) compared the specimen he subsequently described as hendersoni only 

 with species he had tabulated as Distira, not heeding the many extremely close 

 affinities this specimen bears to nigrocinda. In describing the specimen he calls the 

 upper part of the divided second supralabial a loreal, the upper part of the third a 

 prseocular, and the upper parts of the fourth and fifth suboculars. He says that no 

 labial touches the eye on the left side, and only the fourth on the right side. Now 

 it appears to me obvious that the supralabials should be considered as follows on the 

 left side : 8, if (f , f , f), | . On the right side in this specimen they are 8, if (f, 4 f ) -f. 

 On both sides three shields touch the eye. A comparison of these figures side by side 

 with those of P. cyanocinda and A. stokesi shows how complete is the analogy. In 

 the majority of species the third and fourth supralabials touch the eye with great 

 constancy, though they may be divided or not; in many species, however, examples 

 are to be found in which the fifth also finds contact. The result is that with the one 

 or two exceptions first noted these shields do not assist classification in any way. 



Temporals. — These shields have been conceded, I consider, undue prominence in 

 classification ; for although it is true that a single large anterior shield is to be seen 

 with great constancy in many of the species including many of the genus Distira, such 

 as gracilis, cantoris, fasciata, obscura, etc., it is equally true that in many of the species 

 of Distira especially, these shields present in many individuals departures from the 

 normal. As in the case of ftrceoadars and postoculars , the number of these shields 

 depends, to a large extent, upon the tendency of the supralabials to subdivision, for 

 many herpetologists regard as lower temporals what appear to me to be the upper 

 parts of divided supralabials. I find, however, that even when these shields are viewed, 

 as I regard them, they vary considerably in the individuals of many species, and 

 their value has, I think, been overrated. There are some instances of an abnormal 

 condition in these shields prompting the creation of a new species. 



Infralabials. — I regard as infralabials only those enlarged shields which are in 

 contact with the sublinguals. They are distinctive and of generic value in one 

 instance, viz., Emydocephalus , where the second of the series is a very long shield 

 bordering most of the lower lip (see fig. 4B) ; specifically their value is but limited. In 



