328 MR. R. OWEN ON THE ANATOMY OF LINGUATULA TANIOIDES., 
ruginous colour ; it then becomes narrower, and afterwards continues of the same dia- 
meter to its termination at the anus. 
When a portion of the oviduct is viewed through the microscope, its coats are seen 
to be thin and transparent, and not closely embracing the ova, but thrown into folds 
here and there. When cut across, the ova cannot be squeezed out, but adhere to the 
oviduct and to each other by a fine connecting cellular substance. They are of aslightly 
flattened oval form, about -+,th of an inch in the long and =+,th in the short diame- 
ter, filled with a clear yellow finely granular substance. This is invested with its proper 
membrane, and on one side this membrane recedes from the outer coat, leaving a clear 
space, where doubtless the cicatricula, or germ, is situated. The ova are of a firm re- 
sisting texture, and do not lose any of their form or contour by drying. Hence they 
may probably remain long under very different circumstances, preserving their vitality, 
and ready to take on the actions of development when in a fit situation. 
Cuvier rightly observes of Linguatula Tenioides, ‘‘ C’est le ver intestin ot l’on voit le 
mieux le noeud cérébral et les deux filets nerveux!.”” M. De Blainville, who adopts the 
observations of Cuvier on the other parts of the anatomy of Linguatula, is silent with 
respect to the nervous system. Rudolphi seems doubtful as to the nature of the chords 
which Cuvier describes, and confesses his inability to detect a nervous ganglion. This 
part was, however, very conspicuous in the specimen here described, such as it is deli- 
neated in the accompanying figure of the nervous system. It is situated between the 
mouth and the commencement of the oviduct, and consequently is subcesophageal, 
and not cerebral. Eight pairs of nerves may be distinguished, going from it in a ra- 
diated manner. ‘The two anterior filaments pass forwards on either side of the eso- 
phagus, but they could not be traced to a junction above that tube. The small lateral 
filaments terminate at the bases of the fossa on either side of the mouth. The posterior 
pair are the largest; they pass over the ducts of the ovaries and testes immediately 
before these join the oviduct, and then run down the sides of the ventral aspect of the 
body, about a line apart from each other, at first wavy, where we may suppose the 
contractions of the body to be greatest, and afterwards straight, gradually becoming 
wider and less distinguishable from the longitudinal fibres of the integument. 
This form of the nervous system is similar to that which Cuvier originally ascribed 
to the genus Ascaris, in which he considered as nerves the two white chords which 
are continued separately along either side of the abdominal region, from one end of the 
body to the other?. But repeated examination of this and other genera of Nematoidea, 
instituted for the purpose of determining a preparation of the Ascaris Lumbricoides 
dissected by Mr. Hunter, to display its nerves, has subsequently demonstrated the 
correctness of M. Otto’s description of the nervous system in those Entozoa. In this 
respect, as well as in the condition of the generative system, Strongylus, Ascaris, and 
other Nematoidea, differ so widely from Linguatula that the latter ought to constitute 
the type of a distinct order in the class Celelmintha. 
The disposition of the nervous system in Linguatula is in some respects similar to 


' Régne Animal, ed. 1., tom. iv. p. 35. 2 Lecons d’Anat. Comp., tom, il. p. 357. 
