686 DB. H. CHARLTON BASTIAN ON THE ANATOMY AND PHTSIOLOGT 



thin-walled ovoid sac (Plate XXVIII. fig. 20), with no very definite contents*. Probably 

 a somewhat similar structure obtains in all these four genera. Ebeetii states that he has 

 seen in some marine Nematoids the ventral gland composed of two similar parts termi- 

 nating at a common ventral aperture f, which is an arrangement identical with what 

 has now been recognized in many parasitic species. I have seen distinctly in Strongylua 

 Jilaria two elongated glandular bodies terminating by a short common portion, which 

 opens externally by a single median orifice (Plate XXVII. fig. 8). Each of these bodies 

 has the same structure as the single gland met so commonly amongst the free Nematoids, 

 that is to say it is white in colour and dilated at its posterior extremity, enclosing granular 

 contents and a clear, homogeneous, nucleiform body. These glands are, however, longer, 

 and extend further backwards than any we have yet met with. Mehlis:}: appears to 

 have recognized the dilated portions of these organs in Strongylus hypostomvs as long 

 back as 1831, whilst Eberth has lately recognized the entire organs m Strongylus retor- 

 tcpformis, S. commutafus, and *S^. striatus ; two posterior tubes were also spoken of by 

 Von SiEBOLD in connexion with the ventral aperture of Strongylus auriculans, so that I 

 think we may fairly look upon this as the typical form of the organ in the genus Stron- 

 gylus. Similar organs are described and figured by Kuchexmeisteb§ as existing in 

 Anchylostomum duodenale, and by Eberth || in Sclerostomum dentatum, whilst I have 

 myself recognized the outlet and commencement of the tubes in Sclerostomum equinum^. 

 In Heterakis acuminata there is a large transverse opening in the ventral region opposite 

 the termination of the oesophagus which communicates with a dilated termination of 

 the ducts, though I could recognize no distinct ampuUa-like body, such as was 

 figured by Schneider**. This was one of the early species in which two posterior tubes 

 were traced in connexion with the ventral aperture by Von Siebold, which are, I suspect, 

 similar in character to those which we have just been describing. I have also recog- 

 nized a venti'al opening with a large tube proceeding from it in Heterakis vesicularis, 

 which I think will very likely prove to be the terminal portion of two similar glandular 

 bodies. This structure does not seem to have been noticed by Eberth, since he men- 

 tions nothing of it in his account of the anatomy of the animal. 



* This tube gradually becomes lost to view over the intestine, and Davaine (Rech. sur I'Anguill. du ble 

 nicUd, 1857) imagined it to be an excretory duct in connexion with the cellular lining of the alimentary canal. 



•)• I have met with quite an exceptional condition of things in Leptosomatum dongatum. In this animal there 

 are two lateral tubes extending along by the side of the cesophagus for about two-thirds of its extent, each of 

 which opens by a lateral aperture on either side of the head, close to the mouth (Trans, of Linn. Soc. voL xxv. 

 pi. xii. fig. 156). In structure each tube much resembles that of a ventral gland, which, however, is absent in 

 this and two or three other allied species at present located in the same genus. Are they homologous with the 

 salivary tubes described by Owen in Chmthostoma^ 



% Oken's Isis, 1831, p. 81. Taf. ii. fig. 6. Mehlis thought these organs opened into the mouth, and fancied 

 they poured out an irritating fliuid destined to increase the secretion of the mucous membrane to which the 

 animal was attached. 



§ Syd. Soc. Translation, 1857, p. 385. || Untersuch. uber Nemat. p. 66. Taf. xviii. 3. 



% The Strongylus armatus of many authors, and the Sclerostomum miHatum of Kudolphi and DiEsrifG. 



•* MtLLLE's Archiv, 1858. Taf. xv. fig. 7. 



