NEUROLOGICAL NOTES FROM THE BIOLOGICAL 

 LABORATORY OF DENISON UNIVERSITY. 



The following notes are derived from the memoranda taken 

 during the preHminary studies of various members of the labor- 

 atory corps, and are gathered at this time in the hope of calling 

 the attention of others to points in course of elaboration. The 

 undersigned acknowledges responsibility for the morpological 

 generalizations involved. C. L. Herrick, 



I, Selenka's "Pharyngeal Sac" in the Duck. 

 By H. H. Bawden. 



In his monograph on the development of the opossum 

 [Studien iiber Entwicklungsgeschicte der Thiere. Heft. IV. 1887] 

 Selenka describes a branched diverticle of the pharynx immedi- 

 ately back of the pharyngeal velum. 



In the case of embryos of five days the glandular organ 

 has attained its maximum development. A few hours earlier a 

 connection can be demonstrated with the chorda dorsalis which 

 is so direct and obvious as to admit of no doubt that there is 

 ontogenetic connection between the two structures. The 

 pharyngeal sac is very transitory and leaves no trace behind it 

 after the seventh day. It appears earlier than the hypophysis 

 and has all the characteristics of a rudimentary organ. The 

 tubular portion which communicates with the pharynx is hollow 

 while the remainder is solid and variously lobed and divided, 

 one lobe only being in communication with the chorda. 



The author says : — "Die morphologische Bedeutung der 

 Gaumentasche konnte gleichwohl mit Sicherhelt festgestellt 

 werden." " Damit ist der Nachweis erbracht dass die Gaumen- 

 tasche nichts Anderes ist als das verdickte, lappig verzweigte 

 und ausgehohlte Vorderende der Chorda dorsalis, mit anderen 

 Worten, die vordere Chordahohl oder Chordatasche ! " 



