298 MR. H. A. BAYLIS ON THE 



though chloride of gold gave useful results in one particular, as I hope to 

 show, yet for this purpose it was equally unsuccessful. 



It now remains to describe the structure of the epidermis, and it is chiefly 

 here that my account, I believe, differs from those previously given. 

 M. Jobert was unable to study the epidermis, as it was lacking in the speci- 

 men used by him, owing to imperfect fixation. He mentions, however, that 

 on the stem and branches of the tentacle dermal papillae are present, 

 exactly like those of the barbels of other species, in which they are usually 

 surmounted by taste-buds in the epidermis. Oue might, therefore, expect 

 to find a taste-bud in this instance wherever there is a papilla. This, how- 

 ever, does not seem to be the case. A. Zincone [5] gives some account of 

 the cellular elements of the epidermis, and a figure of a transverse section 

 of the tentacle. He does not mention the ])re3ence of any taste-buds, 

 either on dermal papillae or anywhere else ; but he mentions certain other 

 kinds of cells, to which I shall have occasion to refer later. His figure is 

 rather diagrammatic, and seems to differ somewhat from his description. 

 He does not show, for instance, the " rilievi papillarl notevoli " of the 

 dermis ; nor any peculiar cells in the epidermis except ordinary mucous cells. 

 Bateson [1] states that he found no sense-organs on the '^ tree-shaped pro- 

 cesses standing up from the anterior nostril and orbit of B. (jattoruginey 



Now, it seems to be tolerably clear that the dermal pa[)illa3 are not the 

 seat of taste-buds in this case. At the same time, I have noticed in a few 

 of my sections, both in this species and in B. ocellar'n^, little groups of elon- 

 o-ated cells extending through the thickness of the epidermis, and having 

 very much the appearance of taste-buds. They do not seem to be arranged 

 on any definite plan, and in fact are so rare that they have the appearance 

 of having " strayed ^^ from a more normal situation. Where they do occur, 

 they always appear between, and not on, the dermal papillae. In fig. 3 is 

 represented such a group of cells from a tentacle of B. ocellaris. The 

 arrangement of the cells in this case seems so definite that I have figured it 

 for comparison with the less convincing example from B. gattorugine shown 

 in fio-. 4 (PL 23). The cells composing these groups do not, it is true, seem 

 quite similar to those of ordinary taste-buds, and they are few in number. 

 But the fact of such groups of cells occurring at all, and of their extending 

 from the basement membrane to an apparently free ending at the surface, 

 is in itself worthy of notice. Unfortunately I have not been able to see 

 whether any nerve-fibres pass to these groups of cells, but it seems probable 

 that such is the case, and that they are sense-organs of some kind, and 

 very possibly true taste-buds. 



These, however, are not the only sense-organs which I believe to exist 

 in these appendages. In sections of the tips of the branches, stained with 

 chloi'ide of gold, I have found a great abundance of peculiar elongated 

 cells running through the thickness of the epidermis, and ending distally in 



