-40- 



Irregular intervals. The wall of the duct is of about the same 

 thickness as that of the gland, but is not thro^yn into folds. 

 The duct diminishes in size somewhat as it passes forr/ards. 



.-^ Asino trace whatever of this basilar or salivary gland 



,' K 



/' 



a©«i4:-fe^<- fx^yad: in even the oldest larvae at hand, which must 

 , Jiave be^en ver;' nearly ready to undergo transforfliation,] t^teu^h 

 V^ several well preserved and stained series w e re axami -ft^, it seemed 

 possible that this gland might have been developed from the ante- 

 rior part of the larval thyroid, or from the pair of deep cili- 

 ated grooves which run forward from the opening of the thyroid 

 and v,'hich are not present, as such, in the adult condition. 



The similarity in the secretion and function of the 

 larval thyroid to the secretion and function of a salivary gland 

 seems to support this view. The author hopes, with the aid of 

 proper material, to be able to prove definitely whether or not 

 there is any relation between the larval thyroid and the salivary 

 gland of the adult Petromyzon. 



