1S91.] ^J-*^ [Cope. 



Cbeisydrus. In Typhlops we liave a still further modification of the 

 tracheal lung. It is without lumen, and is composed of coarse cells of 

 diflerent sizes. These have no communication with the trachea or lung 

 that I can discover, nor any efferent orifice. It has occurred to me that 

 this structure, which extends from the heart to the throat, may not be a 

 pulmonary organ. 



I have referred to the dorsal and ventral positions of the two lungs. 

 The rudimental lung is to the right of the dorsal lung in the Colubroidea, 

 but in the Ilysiidie it is to the left. It is quite questionable which lung 

 this rudiment in this family really represents. In the Typhlopidse, the 

 single lung is on the right side and extends from the heart to the liver. 

 It has the position of tlie rudimental lung of the Colubroidea, and may 

 represent it. I cannot decide this question without further material. In 

 Glauconia there is but one true lung, and this is ventral in position, and 

 originates to the right of the heart, so that in this genus also it may repre- 

 sent the rudimental lung of the Colubroidea. There is here no tracheal 

 lung or organ.* 



I now give a synopsis of the characters observed in the species ex- 

 amined. 



CATODONTA. 



Qlauconia dulcis B. and G. A single elongate right lung ; no rudiment 

 of left lung. No tracheal lung. 



EPANODONTA. 



Typhlops liberiensis Hallow. ; T. retic.ulatus L. A right lung which is not 

 elongate ; no rudimental left lung. A cellular body surrounding the 

 trachea, and extending from the heart to the throat, without lumeu or 

 connection with the trachea or lung. 



The presence of the tracheal lung (?) and the freedom of the maxillarj'- 

 bone are points of resemblance to the Solenoglypha ! 



TORTB,ICINA. 



llysiidm. 



Two lungs, the ventral one to the left side of the middle line, rudi- 

 mental, but lined with pulmonary tissue like the other lung, and less 

 reduced than in the Colubroidea. 



CyUndrophU maculata L. The right lung extends only to the liver. 



llysia scytale L. The right lung is larger. 



Rhinophidm. 



RJiinoplm oxyrhynchus Schn. One large left lung and very small 

 Ci mm.) right lung ; no tracheal lung. Contrary to the statement of 

 Stannius above quoted, as in Colubroidea generally. 



*Cf. Peters, Reise nach ilozambiqioe, iii, p. 100, PL xivA, 1882. 



