— 134 - 



1. Development and Morphology of the Collar. 



The development of the collar has formerly been mentioned 

 by Faivre and Mac far lane. Faivre's(3) description is very 

 unclear, and contains no explanation at all of the question, as to 

 where in the adult pitcher-rim the primary margin is to be found. 

 He says: "De chaque cote de la saillie mediane (of the lid), un 

 arceau se prononce et isole, en formant voiite, I'opercule d'avec 

 la parol urnaire; celle-ci se dejette en dedans, formant de chaque 

 cote de I'opercule comme une saillie en corne d'abondance; telle 

 est I'origine du bourrelet qui borde I'ouverture operculaire et dont, 

 au debut, la constitution histologique semble la meme que celles 

 des autres parties de la parol" (pag. 196). The stage of develop- 

 ment shown in Faivre' s paper is the same as that in my Fig. 1. 



Macfarlane (11) says more peremptorily, in 1889: "The mode 

 of formation of the corrugated margin is easily explained. It results 

 from flattening out the orifice rim externally and internally and 

 curving over of each upon itself" (pag. 259). Macfarlane here 

 evidently takes all the corrugated rim to be the primary margin, 

 but there is also, besides this, the possibility of the latter existing 

 either in the outer or in the inner border of the collar. This 

 question is so much the more interesting, as Macfarlane (13), in 

 1908, explains the mode of formation of the collar in a manner, 

 quite different from that of 1889. He says: "The typical peristome 

 (or corrugated rim) is formed in part from incurving of the margin, 

 which up to the period of opening of the young pitcher is a uniform 

 rim that projects upward under the closely fitting lid. In part 

 also it results from growth and recurving of a circular area below 

 the rim, that appears as a circular swelling, below and outside of 

 the lid in the young pitcher" (pag. 9). On investigating but a few 

 stages of the development of the young rim, it will be absolutely 

 clear that the two said explanations are not only quite erroneous, 

 but that they are arrived at without any preceding investigation. 



As the figures 1 — 7 show, the primary pitcher-margin is to 

 be found at the outer margin of the adult collar, while the inner 

 margin of this organ, which later on is furnished with marginal 

 glands, arises as a circular swelling on the inner side of the young 

 pitcher. The corrugated surface of the rim must, consequently, be 

 considered as part of the inner wall, which thus appears in three 

 modifications: 1. corrugated surface of the rim, 2. conducting, and 

 3. detentive surface of the pitcher cavity. 



On investigating the margin of the young pitchers, yet in- 



