STRANDED AT LONGNIDDRY. 221 



had, for the most part, been torn off the folds of the palatal mucous membrane, 

 and were included within the tubes of the baleen plates. In some localities, 

 however, some of these papillae still retained their proper attachments to the 

 folds ; and they presented an appearance which reminded one, though on a 

 smaller scale, of that which has already been described and figured in the older 

 animal. 



John Hunter, in his account of the mode of growth of whalebone, 

 pointed out very clearly that a baleen plate is formed upon a thin broad pro- 

 cess of a vascular substance, which fits into the hollow at the base of the 

 plate, and that the first part of the growth takes place on the inside of the 

 hollow. He was also of opinion that the cortical layer of the baleen, and the 

 intermediate substance arose on the surface of the vascular membrane, and 

 were continuous with each other. He showed their relations to hair, nails, and 

 other epithelial structures, and stated that the free surface of the intermediate 

 substance softens like the old cuticle of the sole of the foot when steeped in 

 water. Eschricht and Reinhardt described epidermic cells as continually 

 forming, not only on the pulp-blades, but on the smooth intervals of the palatal 

 membrane between the blades, the cells of the latter constituting the compara- 

 tively soft intermediate substance, whilst those of the former hardened into the 

 horn-like material of the baleen plate. The medullary or tubular portion of the 

 plate formed on the free lower edge of the pulp-blade, and on the numerous, 

 soft, elongated, filamentous papillae which fringe it, whilst the cortical layer of 

 the baleen plate formed on the free lateral surfaces, and inner and outer edges 

 of the pulp-blade, which it ensheaths. 



This description by the distinguished Scandinavian anatomists is, I believe, 

 as far as it goes, perfectly accurate ; but the observations which have just been 

 recorded enable me to supplement it with some new and important particulars. 

 For, in addition to the elongated, filamentous, vascular papillae of the tubes, 

 two other sets of vascular papillae have been observed — a cortical and an inter- 

 mediate — each of which has its appropriate epithelial investment. Hence we 

 may now state, that each of the three great groups of epithelial cells found in 

 the baleen wreath takes its rise from, and constitutes the epithelial investment 

 of, a distinct set of vascular papillae. The cells which form the tubular lamellae, 

 are the cornified epithelium of the filamentous tubular papillae : those which 

 form the peripheral or cortical lamellae are the cornified epithelium of the cor- 

 tical papillae ; whilst the softer intermediate substance consists of the epithelial 

 cells, which invest the sides and summit of the intermediate papillae. 



Many anatomists, in discussing the characters and morphological position 

 which whalebone occupies amongst the textures, have compared it with the 

 teeth, and have regarded it as a special modification of the dental tissue, 

 springing from the surface of the palate. But it seems to me, that a more exact 



VOL. XXVI. PART. I. 3M 



