1895.] LTTNGS OF SNAKES, AMPHISBj5:NIDj5;, ETC. 695 



animals given with greater accuracy and preciseness \ and have in 

 different places hints that Duvernoy had noticed that it was the 

 rule for the left lung to be rudimentary in Snakes ^ much is 

 from our present point of view left vague ^, and there seems to be 

 at least one error*, which is sufficient to prevent him arriving at 

 a correct generalization. 



(v.) Stannius [(5)] errs in saying that the AmphisbsenidiB 

 agree with a number of other Snake-like Lizards which he 

 mentions in having the left lung reduced [I. c. p. 206 and note]. 

 As to Snakes, he mentions a number of kinds, and states 

 whether they have more than one lung, but he does not say 

 whether it is the right or left lung that is reduced. 



(vi.) Milne-Edwards [(6)] gives a resume with references to the 

 Uterature of the subject. "While, however {I. c. p. 308, note), he 

 says that it is the left lung which is the smaller in Pythons, Boas, 

 and Slowworm, and that it is the right which is rudimentary in 

 Amphisbaenidae, at the top of the next page he says (speaking of 

 Snakes) " I'atrophie du poiunon porte tantot a droite, tantot a 

 gauche." 



(vii.) The recognized text-books and encyclopaedic sources of 



^ Thus, on p. 37, Duvernoy rightly states that in Csecilians the left lung 

 (not the right, as Meckel had stated) is mdimentary, and on p. 38 gives exact 

 measurements of the two lungs in different species of these Ampliibians. On 

 p. 32 he rightly repeats that the left lung of Aiiffuis fragilis is the smaller. 



^ Thus, I. c. p. 33, after describing the lungs of Eryx turcicus [this should be 

 a synonym of Eryx jaculus, L.], he adds, " Nous verrons dans les details de la 

 structure de ces deux sacs que le gauche repond au poumon rudimentaire des 

 autres Ophidiens." 



Again, on the same page, he describes the left lung as rudimentary in " I'H^- 

 t6rodon tachete " [Heterodon platyrhinus, Latr.], and, as will be noted below, 

 p. 701, this is a Snake in whose case, if in any, it would be most natural to fall 

 into the error of describing the rudimentary lung as the right. 



Again on p. 36. After stating that there is no trace of a " second " lung in 

 certain species of Vipera and other Snakes, he adds, " Mais il y a un rudiment 

 du poumon gauche dans I' Acanthophis tortor . . ." — a passage which makes one 

 think that though in various places he used the vague expression " deuxieme 

 poumon," he meant " poumon gauche." 



^ Thus on p. 32 we are told which lung is the smaller in Pseudopus pallasii 

 [Ophisauriis apus, Pall.], Ophisaurus ventralis, and the Amphisbsenidse. In this 

 1840 edition of the ' Le9ons,' as in the 1829 edition of the ' Eegne Animal,' 

 these snake-like forms are classed with the Snakes, and if, in accordance with 

 the preceding note, we credit Duvernoy with recognizing that it is the left lung 

 which is reduced or absent in Snakes, we must on the other hand note that he 

 fails to remark that the Amphisb£enid£e differ from Snakes and other snake-like 

 forms in having the right, and not the left, Ivmg reduced or rudimentary. 



* On p. 28 we are told that " Bipes lineatus" has " le poumon droit moitie 

 plus court que le gauche." Comparing this note with the corresponding 

 passage of the ' Begne Animal ' of 1829 (from which Duvernoy, in a note on 

 p. 37, explains that he is quoting certain other statements), I gather (see 

 ' Regne Animal,' 1829, torn. ii. p. 65) that he refers to Scelotes bipes, L. 

 [Brit. MuB. Cat. Lizards, vol. iii. p. 414] ; and if so he is mistaken, for this 

 Lizard is no exception to the general rule, but has the right lung longer than 

 the left. 



I do not censure Duvernoy for making the not uncommon error of confusing 

 right and left. But this error, to my mind, discounts the adjoining statement 

 about the lungs of Chirotes, as to which see below, pp. 702 & 703, 



