The Anatomy of Chlamydoselachus 407 



one-third of the distance from the apex of the pyloric valve to the beginning of the valvu- 

 lar intestine. A probe inserted into the pocket readily entered the common bile duct 

 (c.b.d.) which extends anteriorly. A similar but slightly larger pocket occurs in specimen 

 No. Ill; it is situated a little further caudad, rather more than halfway toward the valvular 

 intestine. A probe passed into this pocket did not find the opening of the bile duct. 

 A bile duct could not be found in the vicinity, but this was probably because the region 

 had been mutilated. In specimen No. II the pocket, as such, could not be found, but 

 a channel or canal leads from the cephalic end of the valvular intestine into the rather 

 thick, contracted wall of the bursa entiana. This channel was probed. After proceeding 

 for a distance of about 15 mm. cephalad within the wall of the bursa, the probe entered 

 the bile duct which extends anteriorly. The channel is, therefore, an extension of the 

 bile duct caudad within the wall of the bursa entiana. 



In specimen No. I the inner surface of the bursa is fairly smooth save in a region 

 extending caudad from the pocket which forms the opening of the bile duct. This area 

 is traversed by longitudinal folds similar to those shown in Text-figure 73- In specimen 

 No. I, these folds extend along the inner surface of the outer wall of the pocket and are 

 visible through its thin inner wall. In specimen No. Ill, where the bursa is greatly 

 expanded, its inner surface is smooth except that the area which in specimen No. I is 

 cast into longitudinal folds, is here somewhat rough and flaccid. In specimen No. II, 

 where the bursa is strongly contracted, its entire inner surface is cast into strong lon- 

 gitudinal folds. The longitudinal canal within the wall of the bursa, which communi- 

 cates with the bile duct anteriorly and opens into the valvular intestine posteriorly, was 

 opened by a longitudinal incision after it had been probed. Its inner surface is very 

 rough, with many small papillae like those found in the upper end of the valvular in- 

 testine. Thus, in the character of its lining, this channel resembles the valvular intestine 

 and differs from the bursa entiana. It constitutes a decided variation from the usual 

 condition in which the bile duct enters the bursa entiana through a funnel-shaped pocket. 



Hawkes (1907) described and figured (my Text-figure 73) a pocket situated nearer 

 the valvular intestine than the pockets described in my specimens No. I and III. The 

 flap forming the inner wall of the pocket figured by Hawkes is not so well developed as 

 in my specimens I and III, where its free edge extends in a straight line transversely 

 or somewhat obliquely. The condition that I have described in specimen No. II, whereby 

 the bile is conveyed through a special channel in the wall of the bursa directly into the 

 valvular intestine, apparently has not been observed by any other investigator. 



In Heptanchus (Daniel, 1934, Figs. 120 and 123) the middle intestine or duodenum, 

 corresponding to the bursa entiana of Chlamydoselachus, is not sharply marked off from 

 the valvular intestine. Daniel (p. 124) states that "the valve of the spiral intestine extends 

 forward throughout the length of the middle intestine and touches the pyloric valve.'' 

 This contrasts strongly with the simpler condition in Chlamydoselachus, already 

 described. 



