The Zoologist— April, 1869. 1627 



positive. The following appear to me the more appreciable differ- 

 ences, none of which can however be regarded as very striking : — 

 First, the nose of Stirpium is the more obtuse and rounded, the nose 

 of Agilis the more acute ; secondly, the legs of Stirpium are the 

 shorter, as also is the tail ; thirdly, Stirpium is the larger species ; 

 fourthly, in colour the females are very similar, but the males of 

 Stirpium are much greener than those of AgiWs ; Ji/thly, I have de- 

 scribed Stirpium as having palate teeth — Agilis has none ; sixthly, 

 the mode of reproduction is different — Stirpium, so far as observed, 

 is oviparous, Agilis is what is termed ovo-viviparous, that is, the 

 eggs are matured in the ovary of the female, but the young are ex- 

 truded in a living and active state, the rupture of the shell or 

 membrane covering the egg probably taking place, as Mr. Bell has 

 suggested, in the act of parturition : this learned author also remarks 

 that the young when brought forth are capable of running about, and 

 "very shortly afterwards of taking their own food," an expression that 

 seems to imply that in their earlier days they receive some kind of 

 assistance in feeding : this inference may not be intended. 



I trust I may be pardoned for writing of the character by which 

 this species is distinguished in a somewhat less decided tone than has 

 been adopted by more authoritative herpetologists. I confess to feel- 

 ing a doubt as to the value of this character as observed ; we want 

 repealed observations of the same kind, and although the theory is 

 beautifully illustrated by Mr. Bell, who represents one species in 

 solitary and apathetic grandeur, and the other surrounded by her 

 little ones as a hen with her chickens, this is scarcely the evidence 

 that satisfies a naturalist. The Age of Romance in Natural History 

 has been succeeded by an Age of Caution, which almost amounts to 

 scepticism ; both extremes are perhaps to be avoided, but the latter 

 can scarcely lead us into glaring errors, a result which the former may 

 now and then successfully achieve. Moreover, herpetologists are now 

 so well aware that this physiological character is of such frequent 

 occurrence amongst reptiles, and if employed indiscriminately would 

 associate such dissimilar forms, that instead of employing it as a 

 generic diagnosis it would be far better to note its occurrence when 

 observed, without laying any particular stress on its value. It will 

 not onl)' be found frequent among the Lacertinidse, the Scincoidae and 

 the Colubridse, but it will appear exceptionally in species always 

 regarded as oviparous. 



