18 PRANK B. BEDDARD 



obviously like those of the developing teeth of the older 

 foetus described by Pouchet and Beauregard as regards these 

 outgrowths. But there is one important difference which 

 is particularly to be noted. In my foetus the outgrowths are 

 always on the labial side ; but the figures of the two writers 

 just referred to show that these outgrowths may be also on 

 the lingual side, a fact which will have to be borne in mind 

 in considering the nature of these parts of the tooth germs of 

 the cachalot. They figure two sections in which the outgrowths 

 are on the lingual and not on the labial side (4, PI. vii, figs. 3 

 and 5). Furthermore, in the older foetus these outgrowths may 

 become, or be accompanied by, a luxuriant crop of similar out- 

 growths (Pouchet and Beauregard, 4, PL vii, fig. 1) on the 

 same side as the single outgrowth or from the oesophageal 

 epithelium (4, PI. vii, fig. 5). I have seen nothing of the kind 

 in my specimen. The nearest approach to it is the double 

 outgrowth (Text-fig. 11) in my specimen. Finally, I call 

 attention to the fact that in one section represented by Pouchet 

 and Beauregard there are two outgrowths precisely as in several 

 sections of the series from my younger foetus (4, PI. vii, fig. 4). 



I should mention also that in my specimens one of the two 

 outgrowths only, or it may be two where there are two or three, 

 certainly corresponds to the diverticulum or diverticula of the 

 tooth follicle to which I have referred on a previous page. 

 I am not sure whether this is always the first of the series where 

 there are two or three ; for the great development of the cavity 

 prevents an accurate fitting to the enamel organ. It should 

 be noted also that the long ' stalk ' of these lateral outgrowths 

 ending in a swollen extremity reproduces more exactly the form 

 of the stalked tooth germ of which they are an outgrowth than 

 in the case of the older foetus. This will be apparent from 

 a comparison of Text-figs. 9-11 with those of the French 

 authors. What are these outgrowths of the dental lamina ? 



Messrs. Wilson and Hill (7, PI. ii, figs. 52-4, woodcut figs. 2, 

 3, pp. 568, 509) figure and describe certain outgrowths from the 

 dental lamina of marsupials (in Perameles) on the labial 

 side, and call attention to the reference by the late Mr. Martin 



