ENTOZOA. 71 



better adapted for trituration than any that seems hitherto to have 

 been detected in the Entozoa, is conformable with the laws which 

 regulate the coexistence of the salivary apparatus in higher animals. 

 Cloquet supposes that the thickened glandular parietes of the oeso- 

 phagus in the Ascaris lumhricoides may provide a secretion analogous 

 to that of salivary organs. Diesing * has described secerning caecal 

 tubes analogous to those in Gnathostoma in species of his genus 

 Cheiracantlms, in which he, likewise, considers them to be salivary 

 organs. Mehlis has also described, in the Strongylus hypostomus, 

 two white organs with blind extremities, which are extended into the 

 abdominal cavity on each side the intestine, and which appeared to 

 him to terminate in the animal's mouth. These glands Mehlis sup- 

 posed to pour out an irritating liquor, which excited an increase 

 of the secretion of the mucous membrane, to which the parasite 

 was attached. Dr. Bagge f has more recently described and figured 

 a pair of blind secerning tubes in the Slrongylus auricularis and 

 in the Ascaris acuminata, which unite and terminate by a common 

 transverse fissure on the exterior of the animal, at a short distance 

 behind the mouth, and to which he assigns the same irritating office 

 as that attributed by Mehlis to the glands in the Slrongylus hy- 

 postomus. 



The alimentary tube in a species of Ascaris infesting the stomach 

 of the Dugong is complicated by a single elongated csecum, arising 

 at a distance of half an inch from the mouth, and continued upward, 

 so that its blind extremity is close to the mouth. From the position 

 where the secretion of this caecum enters the alimentary canal, it may 

 be regarded as a primitive rudiment of the liver. 



The generative organs of the Ccelelmintha are more simple than in 

 androgynous Sterelmintha, or even than in the dioecious Echino- 

 rhynchi ; yet they are adapted for the production of a surprising 

 number of fertile ova. In the Linguatula the organs of both sexes, 

 and especially of the female, are more complex than in the Nema- 

 toidca : I shall, however, briefly notice them before proceeding to 

 demonstrate the parts of generation in the human parasites. 



The male Linguatula, as in other dioecious Entozoa, is much 

 smaller than the female : the generative apparatus consists of two 

 winding seminal tubes or testes, and a single vas deferens, which 

 carries the semen from the testes by a very narrow tube, and after- 

 wards grows wider. It communicates anteriorly with two capillary 

 processes, or penes, which are connected together at their origin by a 



* Annalen des Wiener Museums, Bd. ii. 1839. 



•j- De Evolutione Strongyli auricularis, &c. 4to. 1841, p. 13. 



F 4 



