AXNELIDES. 605 



probably the orifice of the oviduct. The Intestines are in 

 the form of diverging caeca, "and the observations of Mul- 

 LER leave little room to doubt that the mouth serves also 

 as an anus. Some of the species spin threads, like the 

 slugs. They are oviparous, or propagate by spontaneous 

 division. P. nigra is the type of this genus. 2. Dalyel- 

 lla. Mouth a simple slit, placed anteriorly. D. graminea. 

 This genus I have named in honour of an acute observer 

 of nature, John Graham Dalyell, Esq. whose work on 

 the Planarias * exhibits much patient research, and should 

 be perused with care by all who devote themselves to the 

 study of the habits of minute aquatic animals. 



2. GoEDiusiD.E. Ventral surface not fitted to act as a 

 foot in crawling. Locomotion is executed by twistings of 

 the body, which is narrow, and very long. There are two 

 genera : 1. Gord'ms. Mouth terminal, tail divided. The 

 G. aquaticics is the type (of which G. argillacetis is only a 

 variety.) It is probable that some species otFilaria, which 

 have been found in soil, detached from the animals in which 

 they ordinarily reside, may have been referred to this ge- 

 nus. 2. L'lneus. Mouth a longitudinal slit under the 

 snout. This jjenus was instituted in Sowerby's British 

 Miscellany, Tab. 8. (1806,) for the reception of the sea 

 long-worm of Borlase, ('* Cornwall^'' p. 255, Tab. xxiv, 

 113.) CuviER instituted, in 1817, his genus Nemertes for 

 the reception of the same animal. There are several spe- 

 cies natives of this country. 



• " Observations on some interesting phenomena in Animal Pliysiology 

 exhibited by several species of Planariae." — Edin. 1814. In this work, the 

 conjectures of Muller (Hist. Ver. i. p. 62.), regarding the use of the pro- 

 boscis, have been confirmed, the anterior mouth in Dalyellia ascertained, and 

 the manners of eight native species determined. 



