NORTH AMERICAN ANTHURUS. 495 



not only that in this species medullary extrusions have occurred laterally along six 

 longitudinal lines in the region of the arms, as in the Clathrus, but that such extrusion 

 upward and outward has also occurred from the upper end of the medullary column. 



With regard to the last question, as to whether in an earlier stage the gelatinous 

 masses of the peridium were connected down to the base with the column of medullary 

 tissue in the main central cavity of the stipe, 1 think that an answer in the negative may 

 be safely ventured. C. columnatus has such connections, and they determine the 

 mature form of the fungus. Were such connections originally present in A. borealis, 

 some slight indications of the fact, as by the directions of the hyphae, or by some slight 

 persisting connection, as by breaks in the uniformity of structure of the fundament of 

 the wall of the stipe, would have been found in some of the sections. After passing 

 into the cortical region, the medullary masses must have crowded their way down- 

 ward into the cortical tissue by the means that in C. cancellatus has compressed the 

 broad masses of cortical tissue shown in Fischer's Fig. 1, of his work already referred to, 

 into the compact plates of his Fig. 2. That the medullary tissue which becomes the 

 gelatinous layer of the volva may crowd its way down into a loose pre-existing tissue 

 was shown by De Bary in his careful observations upon the egg of Phallus caninus.' 

 But it is quite probable that the greater portion of the length of the gelatinous masses 

 below the level of the arm is to be accounted for by the fact that the arms were at 

 a much lower level when extrusion of the masses occurred, and that while they have 

 retained their connection with the gleba, they have also grown and lengthened with the 

 growth of the stipe and the egg in general. 



Deoelojmient of Anthurus in Next Older Egg. 



Let us now pass to the later development of Anthurus. A more advanced stage 

 than that already considered is shown in Fig. 20. This represents in cross section one 

 of the arms, the surrounding gleba, and the cortical plate passing from the arm through 

 the gelatinous layer of the volva to the cortex. The location of the figured portion in 

 the entire cross section may be seen by reference to Fig. 7, although this latter is from a 

 still more advanced stage of the egg. 



In Fig. 20, one is struck by the great development of the gleba, as compared with 

 that in Fig. 17. Still the repeated formation of new series of folds upon the surface of 

 those already existing would ultimately give a very intricate structure. Indications of 

 such a method of folding were afforded by the younger stage. The great number of 

 small closed chambers shown in this section and in those of later stages seems to show that 



1 De Bary : Beitr. z. raorpli. a. physiol. tier pilze, 1. Keihe, p. 194, tnf. 21), tig. 3 und 4. 



MEMOIRS BOSTON SOC. NAT. HIST., VOL. III. 



