298 Mr. G. Gulliver on the Marginal Nerves of Moss-Leaves. 



A rectilinear or Nodosaria-like Lituola, with an extremely 

 labyrinthic subdivision of its chambers, is common in the Tertia- 

 ries of San Domingo, Malaga, and Tuscany (figured by Soldani), 

 and occurs recent in the mud of the Abrolhos Bank, east of Rio 

 Janeiro. 



18. Lituolites difformis. Ann. Mus. v. p. 243, No. 2 ; viii. 

 pi. 62. f. 13 0, b ; Hist. An. s. Vert. vii. p. 605. No. 2; Li- 

 tuola difformis, Tabl. Enc. Meth. pi. 466. f. 1 a, b. "Fossil; 

 Chalk, Meudon." 



A small irregularly grown Lituola nautiloidea. 

 [To be continued.] 



XXXIII. On the Marginal Nerves of the Leaves of Mosses. By 

 GEORGE GULLIVER, F.R.S., Fellow of the Royal College of 

 Surgeons of England, and Honorary Fellow of the Royal 

 College of Surgeons in Ireland. 



THE term ' nerve ' is here used for the leaf-rib, in the same sense 

 as it has always been employed (though so inconveniently) by 

 botanists, and without the least reference either to the function 

 or to the structure of the very different and more important 

 cords with the same name in the animal kingdom. 



While so much attention has been paid to the mid-nerve of moss- 

 leaves, it seems singular that even the existence of the marginal 

 nerves, identical in structure with the mid-nerve, has not been 

 recognized by systematic writers in Britain. At least, I believe 

 there is no notice of the kind in the classical works of Smith 

 and Hooker, nor in the recent 'Bryologia Britannica' of Mr. 

 Wilson ; and as in this last excellent book the system of Bruch 

 and Schimper is adopted, I presume the same remark will apply 

 to their celebrated 'BryologiaEuropsea/ which I have not yet seen. 

 Moreover, in a cursory reference to M. Schimper's ( Recherches 

 sur les Mousses ' (4to, Strasburg, 1850), I could find no such 

 mention of marginal leaf-nerves. Indeed, descriptive bryologists 

 say " nerve excurrent," ' ' nerve vanishing," and so forth, for the 

 mid-nerve, as if there were no other nerve in a moss-leaf, as, no 

 doubt, is most often, but by no means always, the case, inde- 

 pendently of the well-known double nerve in certain genera. 



This is the more remarkable, as the marginal nerves can be 

 so easily demonstrated by very slight dissection under the micro- 

 scope, while their course and structure will probably be found 

 to afford good specific characters. Schleiden (' Principles of 

 Scientific Botany/ p. 188, transl. by Dr. Lankester, 8vo. Lond. 

 1849) has depicted them in Mnium punctatum, and justly ob- 

 serves that the leaves of Mosses and their nerves merit a more 

 thorough investigation than they have hitherto received. 



