8 Dr. M. Scliultze on the Terrestrial Planariae. 



25. Geoplana {Rhynchodemus) sylvatica, Leidy. Body elongate, 

 fusifoi'in, attenuated in front, pointed behind ; the ventral sur- 

 face somewhat flattened. Colour on the back grey, with two 

 brown stripes along the median line, and a transverse brown 

 spot at or close behind the middle ; belly whitish ; head brown, 

 bent upwards, exhibiting two black, lateral eyes. Length, 2-5 

 lines ; breadth in the anterior fourth, ith line ; in the posterior, 

 \t\\ line. 



Lives between stones, flower-pots, &c., in the gardens of 

 Philadelphia, and also under wood and fragments of bark in 

 the woods of the neighbourhood. 



As a twenty-sixth and last species this is followed by the 

 Geoplana [Planaria) tei'restris, 0. F. Muller, the only species 

 hitherto observed in Europe. This has been already referred to. 



What Darwin and Leidy tell us with regard to the anatomy 

 of the terrestrial Planariae, refers solely to the parts recogni- 

 zable with the naked eye, or with a low magnifying power, such 

 as the alimentary apparatus, the efferent parts of the sexual 

 apparatus, and the eyes; they are fully confirmed by the state- 

 ments of F. Muller, communicated above. The form of the 

 ramified intestine is the same in all as in our well-known fresh- 

 water species ; this is also the case with the position of the 

 buccal orifice. Only the form of the CEsophageal tube differs 

 essentially, as F. Miiller particularly points out, in several 

 species, by the cylindrical form becoming converted more into 

 a trumpet-shape, with repeatedly folded margins to the outer 

 orifice. The genital orifice is situated throughout behind the 

 mouth, and is always simple, by which the terrestrial Planaria 

 are removed from the large marine forms, for a knowledge of 

 which we are especially indebted to Quatrefages *, and some of 

 which I have myself been able to examine f. The penis and 

 seminal ducts have been detected in several species. Where 

 eyes are present there are either ticu, as in G. terrestris and 

 sylvatica, or many, and these are then always distributed on the 

 margin of the animal in groups, at pretty uniform distances 

 apai-t, or more singly. Darwin and Leidy state that they con- 

 tain a refractive body. 



The above statements regarding the position of the buccal 

 and genital apertures do not agree with what Blanchard says 

 of his genus Pulycladus. In this the buccal orifice is said to 

 be in the anterior, instead of the posterior third of the body, 

 the genital orifice still farther forward. From the further 

 description of the animal, however, it appears clearly that these 



* Ami. rles Sci. Nat. 'A ser. iv. p. \'2\). 



t Veihandl. der phys. med. Gcsellsch. in Wiiizbiirg, iv. 1854, p. 222. 



