fijrrow is to prevent the spilling back into the host's voiind of 

 any blood already in the pharynx. The tongue like process also 

 appears to play an essential part in the mechanism of ejection 

 of salivary fluid into the blood as it is being ingested. Since 

 the salivary fluid is discharged into the distal region of the 

 buccal canal, it is assumed to reach the wound in the host (and 

 thus might transmit disease-causing organisms contained in it). 



As stated above, Bertram's study has considerable practical 

 value, but must be read in its entirety to be fully appreciated. 

 It should be noted that Snodgrass (194-8) refers to the tongue- 

 like process as the labrum in his noncommittal review of Bertram's 

 findings and conclusions. 



Alimentary canal ; We now retxu-n to Christophers' (1906) 

 study of 0. savignyi , and it is interesting to note that he found 

 the pharynx to open into the floor of the '*mouth" (buccal canal) 

 in contrast to Bertram's observation on 0. moubata , mentioned 

 above. At any rate, the pharynx leads to a narrow, straight 

 esophagus. The latter, after perforating the central ganglion, 

 enters the enormous saccular midgut, which, with its diverticula, 

 forms the great bulk of body contents. Posteriorly, an extremely 

 fine canal, which appears to be a fionctionless rudiment, joins 

 the midgut with the rectal ampulla (but in 0. moubata even this 

 is absent and the alimentary canal ends in a completely closed 

 sac separated from the rectal ampulla) (see below), 



Esophagvts and prove ntricular fold . The esophagus, a short, 

 straight tuiDe perforating the centraTganglion in its course 

 from pharynx to alimentary sac, is lined with a layer of clear 

 columnar cells with small nuclei. The irregular outlines of these 

 cells are mutually adapted to one another in a dovetailing arrajige- 

 raent. At the juncture of the esophagus and large blood sac there 

 is a small solid organ. This organ, in section, consists of a 

 thick fold of epithelium of the same general character as that 

 in the esophagus but of more columnar and less irregular cells. 

 In the fold are some thick circular bands of muscular tissue 

 and outside are longitudinal fibers passing from the esophagus 

 to the gut. The epithelium of the fold passes imperceptibly 

 into that of the esophagus, but ends abruptly on reaching the 

 wall of the alimentary sac. The organ is very similar to, though 



- 165 



