79 
“tulip-root,” or “ segging.” 
measurement), magnified to a hundred and seventy times the original 
size. 
Fig. 2 represents the front part of the same female specimen seen 
sideways, magnified five hundred times : the “ knotted spear,” the 
absence of which is noted by Dr. de Man as one characteristic of the 
Cephalobi, is a sharp process or instrument at the commencement of 
the oesophagus, by which it is supposed that such kinds of Eel worms as 
possess it prick their food, and thus are able to suck the juices. 
Fig. 8 is a side view of the head, showing details of the mouth¬ 
opening, and magnified a thousand times. 
Fig. 4 is a side view of the tail-extremity of the same female 
specimen, magnified five hundred times. 
Fig. 5 is a side view of the tail extremity of a male specimen, with 
details magnified seven hundred times. 
Dr. de Man gives the description in technical terms in the following 
“Explanation of the Plate. 
“ Fig. 1. Ceplialobus rigidus, Schneider, female specimen, 1*13 millim. 
long, in a lateral view *p. The ovarian tube extends till near 
the anus. 
“Fig. 2. Anterior part of the same female specimen, in a lateral 
view, showing the oesophagus with its posterior swelling con¬ 
taining a valvular apparatus, 5 t°- 
“ Fig. 3. Lateral view of the head, presenting three out of the six 
lobes at the anterior extremity and the buccal cavity, 10 T 00 . 
“ Fig. 4. Posterior extremity of the same individual, in a lateral 
view, 5 t°. 
“ Fig. 5. Posterior extremity of the male, in a lateral view, pre¬ 
senting one of the two spiculse and their accessory piece. Some 
papillae are also visible on the tail. 
“ The transverse striae of the integument have only been figured 
on the figures 3, 4, and 5.” 
The above notes appear to me of great interest: of course in the 
first observation of a new kind of attack it is of the utmost importance 
to be certain that the newly-observed insect or worm is the cause of 
the evil noticed on the plant; and in this case, after very careful 
consideration, looking at the details of growth of the Oat-plants from 
about a week after their appearance above ground, and the obvious 
signs of Eelworm attack present, when sent to me,—together with the 
fact that this Ceplialobus rigidus was present in great numbers, and no 
other kind to which attack could be attributed,—from all this it 
appears to me, as well as to Dr. de Man, that the attack may be referred 
to this cause. 
