6 Records of the S.A. Museum 



maxilla, but li\' means of its forkctl j)ru.\imal end it articulates with a small trans- 

 verse Ijune wliich connects tlie free poi'tion of the maxilla with the palatine. If 

 this trans\erselv placed hone, marked "ec" in the accompanxiny diat^rani. is not 

 liomologous with the ectopter_vgoid of less degraded forms of ophidia. is it to he 

 regarded as a detached, though sutured, portion of the outer extremity of the 

 palatine, or should it be referred to some other bone? 



The pelvis is represented by a single small bone on each side. The arrange- 

 ment of the soft parts generally conforms to the conditions found in other 

 snakes, in which, however, there is considerable diversity, not only in the character 

 and position of the lungs, but in their number also: some snakes ha\e two. one 

 of which, in the majoritv of forms, is more or less rudimentary, whilst others 

 ha\'e Ijut a single lung: the blind snakes ha\e only one true lung: it is placed on 

 the right side and extends from the heart to the liver. Another organ, the so- 

 called tracheal lung, regarded by some as the \estige of a once functional lung, 

 is without cavity, is composed of cells of different sizes, and appears to have no 

 communication with the trachea or lung. It has been suggested that this struc- 

 ture may not be a pulmonary organ. 



Illustrations. ( )wing to the roundness of the bodies (.)f these snakes it 

 is not possible, from a fixed jioint, to see quite half the diameter: it was from 

 such \iew-point that my former drawings were niatle. the result Ijeing that, as 

 regards their upper and lower aspects, the point of contact o{ the head scales 

 with the margin does not coincide. The new drawings accompan)ing this paper 

 are slightly more diagrammatic, inasmuch as the \iew is supposed to subtend 

 exactly half the diameter of the snake, so that the unsatisfactory condition 

 referred to is thereby remedied. All the drawings are larger than life. Init are 

 not to the same relative scale. With one exception, namely, that of 7". -a'aitii. 

 all the admitted species are illustrated, the drawings being prepared under my 

 l)ersonal supervision by my assistant, Mr. Herbert M. Hale, to whom I here 

 express my thanks. 



Terms used. In describing the head of a snake, or indeed parts of other 

 animals, two distinct contours often reciuire to be defined, namely (a) that seen 

 from the side, and (b) that seen from above or below. The words "view" or 

 "aspect" may be used in explanation of an illustration, but cannot well be applied 

 in descriptions where the external contour alone is to be expressed. 



In describing the outline of an object as seen from the side, we have the 

 >imple and exact word "profile." l)Ut there is. as far as I know, no single word to 

 express the outline as seen from al.)o\e or below. 



It is reallv the lateral contour that is sought to be defined, but the use of 

 the wortl "lateral" at once suggests a side view or profile: then the employment 



