200 ON THE NERVOUS SYSTEM OF THE NEMATODA., 
true nerve-fibres, which are best displayed when the ring has 
been boiled in dilute nitric acid, and torn asunder with 
needles. The fibres then exhibit the same structure and 
dimensions as the nervous trunks passing from the ring. 
Besides the fibres, however, the ring also contains bipolar cells, 
though in no great number. 
The ring, as has been said, is closely connected with the 
walls of the body. The connection is effected chiefly by four 
bands, which appear to be, as it were, continued from the 
lateral and two median intermuscular arez or spaces, aud 
by them the ring is divided into four equal portions. But 
it is also closely connected with the muscular system by 
transverse prolongations of the muscle-cells, which consti- 
tute four bands, one of which is attached to each of the 
quarters of the ring, being continuous, as it were, with the 
sheath. 
No further distribution of the nerves appears to have 
been clearly made out, although the author has made nu- 
merous and very industrious researches, which have shown 
him many interesting facts in the minute anatomy and 
arrangement, more especially of the muscular system, for 
which we must refer to the paper itself. 
With respect to organs of sense, he states that in Lnoplus, 
Duj., Phanoglene, Nordm., and Enchilidium, Ehr., eyes are 
indubitably present, although up to the present. time no 
nerves have been traced to these organs. 
Of other organs of sense, he points out certain structures 
which appear to be of the nature of tactile organs. These 
are tubular hollows in the integument, filled with a fine 
granular substance. On the exterior these follicles are either 
level with the surface or form small eminences of different 
kinds. These sort of papille are found in four different 
situations, and they may be classified into—1l. Oral papille, 
varying in number from two to ten. 2. Cervical papillie, 
always two in number, and lateral.* 3. Caudal papillz, also 
always two in number, and lateral.t 4. Copulatory papillee, 
situated in the caudal portion of the male, symmetrically, on 
each side of the ventral median line. No nerves, however, 
have as yet been traced to these organs, though Schneider 
thinks the submedian and lateral nerves go to the oral 
papillee. 
* The organs noticed by Dr. Pagenstecher in Sagit/a gallica would seem 
to be of this kind. (Vid. supra, p. 193.) 
+ M. Bastian, in a paper read before the Linnean Society, and which will 
appear in the ‘ Linnean Transactions,’ describes two organs of this kind (or 
of the next?) in the hinder part of the body in the young Guinea-worm. 
