180 Mr. Thomas Hick on the 



before the Society in the early part of last year. In the 

 preparation of that paper my attention was frequently 

 arrested by the presence of leaf sections intermingled with 

 those of young Calamitean stems, and from certain well- 

 marked characters I concluded that they were the leaves of 

 Catamites. Since then ample proof of the truth of this 

 conclusion has been obtained, and it is now possible to 

 describe the general structure of these, and to give some 

 account of their histological peculiarities. 



Description of the Specimens. 



i. Among the preparations of Catamites in the Cash 

 Collection of Sections of Carboniferous Plants, now in the 

 Manchester Museum, at Owens College, are a few which 

 contain pieces of Calamitean twigs with portions of the 

 leaves still attached. They are very fragmentary, and not 

 in good condition for reproduction as illustrations, but they 

 are sufficiently well preserved for identification. One of 

 them, prepared by Mr. James Binns, of Halifax, is repre- 

 sented in Fig. I, PI. III., which is reproduced from a 

 photograph, and gives a fair picture of the specimen, though 

 it is not so clear and sharp as the specimen itself. At a 

 we have the outer part of the cortex of the twig, and at b 

 the inner part, with the elongated elements carrying black 

 contents described in the paper on " The Primary Structure 

 of the Stem."* Within this is the vascular strand, whose 

 protoxylem elements, in the usual fragmentary form, are 

 seen at x. Then comes the pith p, followed towards the 

 right by a repetition of these tissues, but in reverse order. 

 The pith is interrupted at the node, where we see at n the 

 converging strands of xylem from the two neighbouring 

 bundles. On the left side of the node the basal part of a 



* Loc. cit., p. 162. As the tissue formed by these cells will be referred 

 to again and again, it will be convenient to speak of it simply as " Melasmatic " 

 tissue (/u-iXarr/^a, a black spot). 



