1851.] 283 



Young Gordii possess two circles of filamentary appendages around the pro- 

 boscis, which, at this early period, is alternately protruded and retracted. Whe- 

 ther the sanae motion, and the same appendages, are still present in the adult 

 state, is yet to be examined. Many worms are known to be provided with a retrac- 

 tile proboscis, which they use in perforating the sand and mud in which they 

 live. Gordii might require it to introduce themselves into the living bodies 

 where they are sometimes found. As to the circles of tentacles, they very likely 

 disappear in the adult, while the alimentary canal atrophies, their function being 

 intimately connected with the functions of the latter organ. 



V. 



With regard to the species of Gordiaceae to be admitted, naturalists do not any 

 more agree. 



The most common in Europe is Gordlus aquaticus, L.* The G. marinus and 

 G. aiinulatus of Montague,t are Nemerteae. 



Mr. Charvett describes two others, from the vicinity of Grenoble, (France,) 

 under two trivial names. 



Mr. Dujardinll considers as distinct, from the above, a species from the vicinity 

 of Toulouse, his Gordius Tolosanics. and describes another species, proposing for 

 it the genus Mermis, calling the species M. nigrescens. 



Prof. Siebold has made us acquainted with a second species of Mermis, his 

 M. albicans. 



Mr. BlanchardiT has described one species from Chili, under the name of G, 

 Chilensis. 



Finally, Mr. Ed. Grube** describes another from Africa, which he calls 

 Gordius crassus. 



Before we identify the North American Gordii with any of the above men- 

 tioned ones, we must be prepared to account for many objections which can be 

 made, respecting their having been created identical over such an extensive area, 

 or else of their having migrated naturally, or having been accidentally transported. 



VI. 



We have in the United States one species, which seems quite common in fresh 

 water, and referred by some to G. aquaticus. Rev. Z. Thompson, of Burling- 

 ton, (Vt.), expresses himself in the following terms : " The little animal called 

 the Hair snake also belongs to this order, (annulata,) and to the genus Gordius. 



* Systema Naturaj ed. xii. 1767, p. 1075. 



t Transactions of the Linnean Society of London, vii. 1804, p. 72 and 74. 



J Observations sur deux especes du genre dragoneau qui habitent dans quelques 

 eaux courantes aux environs de Grenobles. Nouv. Ann. du Mus. d'hist. Nat. iii. 

 1836, p. 37. Ann. Sc. Nat. 2d6 ser. ii. 1834, p. 123. Wiegm. Archiv i., i. 

 1835, p. 341. 



II Memoire sur la structure anatomique des Gordius et d'une autre Helminthe 

 qu'on a confondu avec lui. Ann. Sc. Nat. 2de ser. xviii., 1842, p. 129 and 146. 

 Institut., 1842, p. 256. Archives gen. de Medec. xii., 1842, p. 488. 



Entomologische Zeitung, 1843, p. 80. 



11 Historia fisica y politica de Chile, por Claudio Gay. Zoologia iii., 1848, 

 p. 109. 



Troschel Archiv, Sec, 1849, i., p. 370. 



