694 MR. GERAED W. BUTLER OS" THE [NoV. 19, 



contributions to the subject herein discussed. I will here briefly 

 allude to these and to a few other references of lesser importance, 

 partly to do justice to the authors named, and partly to show 

 cause for the publication of this present paper. 



(i.) I have ah'eady referred to the work of Nitzseh [(1)]. His 

 treatment of the matter is excellent, so far as it goes^. 



(ii.) J. F. Meckel [(2) p. 84], using of course an earlier system 

 of classification in discussing the lungs of Snakes, noted correctly 

 that in the Amphisbsenidae the rudimentary lung, if present, is on 

 the right side, but he spoilt this observation by adding that this 

 also was the case with all the " Colubers" he had examined ^ He 

 ^vas again, however, right in saying that the smaller lung was on 

 the left in all the Boas and Tortrix sci/tale, as well as in Anguis 

 fragilis. 



(iii.) In his later work [(3) pp. 259 & 260] he made another 

 mistake in adding Ccecilia, as well as the Colubers, to the Amphis- 

 baenidae as having the rudimentary lung on the right side. He 

 was, however, right in placing Platurus and Ti/phlo23s, as w-ell as 

 the lizards Ophisaurus, Pseudopus, Bipes, and Seps with the 

 Boas, Tortrix, and Anguis of his previous paper, as having the right 

 lung the largest. As to Chirotes, which Amphisbaenid, he avers, 

 has the right lung much the largest, see below, pp. 702 & 703. 



(iv.) The treatment of this subject in the second edition of 

 Cuvier's 'Legons d'Anatomie comparee' [(4)] shows in some 

 respects a marked advance on the papers previously mentioned. 

 Nevertheless, although we ha^'e details with regard to some 



1 Nitzseh, I. c. p. 13, after describing the kings of Lizards, says that Aoiguis 

 fragilis has the right lung rather longer than the left. He then describes the 

 rudimentary left lung of Tro-pidonotus {Coluber) natrix : — 



"In Colubro natrice autem sinistrum liberum, minimum, piso communi 

 parum majorem, tamen cellulosum, dextrum contra maximum, longissimum . . . 

 Quemadmodum vero in isto Colubro, ita in reliquis serpentibus, quibus 

 auctores unum modo pulmonarem foUem tribuunt, hoc organon comparatum 

 [paired] esse autumaveriin. Haud dubie sinister, quanquam minimus, vere 

 adest. Non omnibus saltern serpentibus unum duntaxat pulmonem esse 

 proposita exempla docent." 



The expectation expressed in the last sentence but one is of course not fully 

 borne out. There are a number of Snakes that have no trace of a second lung ; 

 but there are very many in which, as in Tropidonotus natrix, the left may be 

 easily overlooked. I have thought it worth while to quote his words because 

 he was apparently the iii-st to describe this rudimentary left lung, because 

 his description is so good, and because he at once grasped the fact that the 

 rudimentary lung of such a Oolubrine Snake is the left lung — a thing which 

 has always seemed to me pretty obvious, but which has struck some other 

 people differently. 



^ Meckel and Cope have used the terms " Colubern " and " Colubroidea " 

 respectively [see (2) and (7)1 in a wide sense almost co-extensive with the 

 Linnean genus Coluber, so that under these headings come a large majority of 

 known Snakes. This of course adds greatly to the importance of any general 

 statement they make as to Colubers or Colubroidea. Further, if Meckel and 

 Cope do not actually state that the rudimentary lung of these Snakes 

 corresponds to the right lung of other animals, their writings tend to spread 

 this view when, without further comment, they say that this rudimentary lung 

 is " on the right side," or, as Cope, figure it as " right lung," 



