THE NERVOUS AND EEPKODUCTIVE SYSTEMS. 691 



or, if connected, how this takes place. Only so much has been found out, 

 that, besides the longitudinal vessels extending internally, a fine super- 

 ficial vascular network is present here, as in other species. This has 

 not only been established by the facts which we have already com- 

 municated, but has also been corroborated definitely and in detail by 

 the results of Knoch^ and Botticher,^ who have observed in the head 

 of Bothriocephahis a close network of fine vessels, which becomes 

 posteriorly coarser and more widely meshed, and finally (according to 

 Botticher) passes on each side into several wider longitudinal vessels, 

 which are mutually connected by an irregular anastomosis. Moniez 

 estimates the number of these superficial longitudinal vessels at about 

 twenty. As to the connection with the more deeply situated longi- 

 tudinal vessels, nothing is known, nor has any ciliation been yet 

 observed in Bothriocephalus latus.^ 



The Nerve Cords, which can be traced along the whole length of 

 the body, and which with increasing size of the joint become 

 gradually thicker (from 0-25 mm. up to 0-1 mm.), change their 

 position after the disappearance of the deeply seated longitudinal 

 vessels, inasmuch as they are pressed not only farther inward in 

 consequence of the stronger growth of the lateral borders, but also 

 towards the ventral transverse muscles by the testicular sacs on the 

 dorsal surface. They exhibit the same apparently spongy structure 

 as the nerve tracts of the Tmnim, and, like the latter, have been 

 designated by Sommer "plasmatic" longitudinal vessels. Other 

 observers have compared them to the longitudinal canals of the 

 Tcenice, except Eschricht, who thought he had discovered in them the 

 limbs of a bifurcated divided alimentary can^. Cerebral ganglia, 

 if present at all as distinct structures, are at any rate very small 

 and insignificant, as the absence of specialised suckers would indeed 

 lead us' to suppose. It seems probable that the two lateral cords 

 are united at the anterior end of the head by a simple transverse 

 connective. 



The peculiarities of Bothriocephahis, as above noted, may scarcely 

 appear very striking or characteristic ; but it is very different when 

 we turn our attention to the next group of organs. 



The Reproductive Organs. — In the nature and disposition of the 

 genital apertures, in the structure of the uterus, in the arrangement 



^ " Naturgeschichte d. breiten Bandwurmes, " 1862, p. 118. 



" Archiv f. pathol. Anat. u. Physiol, Bd. xlvii., p. 370, 1869. 



' The statement of Moniez {loc. ctt., p. 143) that the vascular network of the head 

 opens externally on the lips of the suckers by a large number of small oscula, requires 

 corroboration. The " ampoules pyriformes," as the oscula are designated, recall the 

 " doubtful bodies," perhaps unicellular glands, previously described (p. 678). 



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