TKANSACTIONS OF SECTION D. DEPT. ZOOLOGY AND BOTANY. 670 



Vermes. 



Only aljout 14 species appear to be recorded ; these are Plauarlans, earthworms, 

 and leeches. 



A list like the above scarcely needs comment. To suppose that in a country 

 from which between 4,000 and 6,000 species of Lepidoptera have been described 

 there are not 1,000 Hymenoptera, less than 5,000 Coleoptera, and, above all, scarcely 

 more than 100 spiders, is absurd. It is evident that our knowledge of the Inverte- 

 brates of India is of the most rudimentary and imperfect description. 



5. On a Fossil Stem from the Halifax Coal-measures. By Thomas Hick, 

 J5.il., B.Sc, and William Cash, F.G.S. 



The stem described is one that has been obtained by Mr. James Binns from 

 the Lower Coal-measures of Halifax, Yorkshire. Though somewhat flattened on 

 one side and imperfect on the other, it is s^iliiciently well-preserved to indicate 

 that it was originally cylindrical in its general form. It consists of a central pith, 

 surrounded by a number of slightly wedge-shaped masses of vascular or fibro- 

 vascular tissue. Outside these masses of tissue, or bundles as they may be called, 

 is a cambium zone, followed by a comparatively thick cortex. Its whole diameter 

 is "147 of an inch. 



T/ie ^jiY/t has a parenchymatous structiu'e quite similar to that met with iu 

 recent herbaceous stems and in the youngest shoots of woody perennials. 



T/ie vasculai- tissue surrounds the pith in a narrow zone, and iu the transverse 

 section bears a remarkable resemblance to the Xylem portions of the fibro-vascular 

 bundles of dicotyledons during the hrst season of growth. It is composed chiefly 

 of vessels of the barred and dotted tj-pes. 



The pith and vascidar tissue combnied form a central cylindrical axis to the 

 stem, which has a diameter of '056 of an inch. 



The cambium layer lies outside the vascular zone, and consists of delicate thin- 

 v.-alled cells, which again remind us of young dicotyledonous stems and branchlets. 

 It is not, however, separated from the cortex by the interposition of any ele- 

 ments having the appearance of phloem. 



The cortex is the most characteristic portion of the stem, and differs from any- 

 thing previously met with in the stems of fossil plants. It is of considerable 

 thickness compared with the diameter of the central axis, and is, apparently, 

 entirely cellular. In the middle portion there is a series of large air-spaces, which 

 run through the stem in a longitudinal direction, and which are destitute of tissue 

 of any kiud. These are separated from one another by thin plates of tissue, one 

 cell thick, which run in a radial direction from the central axis to the periphery. 

 In the possession of these air-spaces, and the histological structure of the paren- 

 chyma that separates them, the fossil agrees very closely with sucli well-known 

 aquatic genera as Myiiophyllum, Hippuris, Hottonia, Potamogeton. With tlie 

 stem of Myriophyllum, indeed, it is almost identical, the radiating plates of paren- 

 chyma met with iu the cortex, exhibiting the same arrangement in both cases, and 

 being destitute of the numerous anastomoses which are met with in the other 

 genera. The chief difference between them is in the vascular axis. In the fossil, 

 this shows the distinction of pith and vascular bundles above-mentioned, but 

 exhibits no trace of a fibro-vascular bundle-sheath. In Myriophyllum the axis is 

 composed of a thin-walled cambiform tissue, intermixed with which, in a more ov 

 less irregular manner, are a few spiral vessels, and the whole is enclosed in a well- 

 detined tibro-vascular bundle-sheath. Though attaching great weight to these 

 differences, the authors do not regard them as absolutely decisive against the 

 affinity of the fossil plant with Myriophylluin. They consider it probable that 

 Mynophyllum and the other genera referred to are tlie existing representatives of 

 plants that were formerly more abundant, and whose tissues were more highly 



