Structure of the Leaves of Catamites. 181 



leaf is still attached. In it we may recognise, with the aid 

 of a hand-lens, the following details : at e, the cells of the 

 epidermis, with thick outer walls, apparently cuticularised ; 

 a.tf the assimilating tissue, composed of thin- walled cells ; 

 at g y a small fragment of protoxylem ; and at m a layer of 

 " melasmatic " tissue similar to that in the inner cortex of 

 the stem. 



From the appearance of the specimen, it would seem 

 that a second leaf originally existed at the same node on 

 the right side of the twig, and at n y we have probably the 

 point of origin of a third. Assuming that this was so, and 

 that the third anterior leaf was opposite a posterior one, 

 the whorl will originally have had four members, a con- 

 dition of things which is suggested by other specimens. 



2. A specimen in my own cabinet, also prepared by Mr. 

 Binns, and for which I am indebted to the generosity of 

 Mr. William Cash, of Halifax, is represented in Fig. 2. 

 The difficulty of photographing was, however, greater than 

 usual, and in consequence the figure does not do it full 

 justice. It represents a longitudinal section of a portion of 

 a very young twig of CalamiteSy with five short internodes 

 within a length of 3^ millimeters. At each node are 

 smaller or larger portions of a pair of leaves, also cut 

 longitudinally, one on each side of the twig. From the 

 appearances it presents I am inclined to think that, as in 

 the preceding case, each node carried a whorl of four 

 leaves, and that the members of successive whorls were not 

 directly superposed. This, however, is rather an inference 

 than an observation. At this stage of development the 

 leaves had an outward and upward curvature, the concavity 

 being on the upper side. 



Coming to the structure, the twig shows a cortex, whose 

 inner layer is distinguished from the outer by the presence 

 of the characteristic " melasmatic " tissue seen in the 

 previous specimen.. This tissue is continued into the 



