Herrick, lVerves of Silurord Fishes. 235 
though in a large specimen of A. melas, whose pit lines pre- 
sent the same appearance as here described, a slit-like pore is 
occasionally seen. Upon inserting a probe a capacious cavity 
is discovered roofed by a thin non-pigmented membrane and 
floored by the sensory epithelium. Iinfer that the strictly 
naked type first described is an imperfect!y developed or imma- 
ture stage of this kind of large pit organ. 
Unlike the terminal buds, these organs are wide at the 
apex, which is often flat topped. The base is still wider by 
reason of the fact that the nuclei of the supporting cells are 
near their bases. The supporting cells are usually more darkly 
stained by the treatment given than are the cells of the sur- 
rounding epidermis. Pear cells are found in the organ in es- 
sentially the same relations as in the other neuromasts, or 
organs of the acustico-lateralis system, though in this case they 
are usually much smaller than in the others. They extend 
scarcely one-third of the way from the apex to the base of the 
organ, and are frequently stained very pale, often invisible alto- 
gether, whereas in the canal organs and small pit organs the pear 
cells are always conspicuous and often much darker than the 
supporting cells. The general arrangement strongly suggests 
the figures given by Kinessury (95) for the naked lateral line 
organs of Amphibia, notably Diemyctylus. In my sections of 
Menidia and Gadus, which were prepared by essentially the 
same method as these of Ameiurus, I was not able to demon- 
strate any pear cells in the corresponding pit organs, though it 
is quite possible that suitable technique would show them up. 
But Miss Crapr’s sections of the sense organs of the lateral 
lines of Batrachus, which are not open to such technical limi- 
tations, likewise do not show pear cells sharply differentiated 
from the supporting cells, and this applies, if I understand her 
correctly, to both the naked neuromasts and those contained 
within the lateral line canals. The significance of the pear cells 
in these neuromasts requires further study. It is clear, at any 
rate, that the pear cells are typically present in all organs of the 
lateral line series, or neuromasts, and that MERKEL’s (’80) dis- 
tinction between these organs and the terminal buds is morpho- 
