OP THE INTEGUMENTS. 77 



The Temporal -plates exist only in conjunction with the 

 occipitals and superior labials, among which they are 

 placed, and on which their number and form depend. 



We have stated above, that the border of the lower jaw 

 is almost constantly furnished with plates, of which the 

 central one is at the end of the muzzle, corresponding to the 

 rostral. The second pair are often prolonged below the 

 chin, to unite with one or two pairs of plates, enclosed 

 between the labials, and distinguished by the name of 

 Mentals or Geneials. Although of a very variable form, 

 they are rarely wanting ; and their lower edge always 

 forms that deep fissure, which so materially contributes to 

 the enlargement of that part of the skin, and which is 

 know^i under the name of Gular Fissure. 



A more extended terminology to indicate those plates 

 appears to me superfluous ; and I shall conclude this 

 section of the work by calling to recollection that it is 

 easy to recognise them, provided attention be given to 

 those terms which are invariably derived from the regions 

 which the organs occupy : it is thus that many of those 

 plates, which extend between the labials and the first ab- 

 dominal bands, and are often divided, bear the name of 

 (rwZar plates ; the last abdominal plate, equally divided, and 

 covering the orifice of the anus, is termed the Anal plate, 

 &c. &.C. 



[As these distinctions, though long employed in Ger- 

 many in the descriptions of Ophidians, are but little fa- 

 miliar to the English reader, the translator has introduced 

 two figures, A and B, PL I., with references to the different 

 plates mentioned in the text. 



A B 



a Vertical plate. n Middle labial. 



b Occipitals. o Accessory labials. 



c Superciliars. p Anterior geneials, or mentals. 



d Temporals. q Posterior geneials. 



e Posterior frontals. r Marginal labials. 



/ Anterior frontals. s Gular scales. 



<j Rostral. t Gular scuta. 



h Posterior oculars. u Abdominal scuta.] 



i Anterior oculars. 

 k Frenal. 



I Nasalr 



