OCR Text |
Show 1899.] ON TWO EARTHWORMS. 803 fig. 2, A & B ) , but it does not reach the margin of the pallium. It is, however, always very near to reaching this margin ; and on one side of one brain it appeared actually to do so through becoming confluent with another fissure of short length. O n the mesial surface of the brain a single fissure (fig. 5, E ) is very plain anteriorly, which curves round the anterior end of the corpus callosum. This is the limbic fissure of Broca, splenial of other authors, and, I presume, calloso-marginal of still others. A very interesting little fissure was observable in the best preserved of the two brains which I bisected longitudinally. This is shown in fig. 5. At the end of the hemisphere is a short vertical fissure (A, B, C) and a shorter one still behind this, and a more faintly marked one in front. It is of course an obvious suggestion that they are the parieto-occipital and calcarine respectively. 9. Notes upon two Earthworms, Perichceta biserialis and Trichochceta hesperidum. By F R A N K E. B E D D A R D, M.A., F.R.S., and SOPHIE M. FEDARB. [Received June 6, 1899.] The first of these species (Perichceta biserialis) was originally instituted more than twenty years ago by M . Perrier1, whose description, however, was only in the nature of a " preliminary communication." The two matters to which he referred, viz. the disposition of the genital papillae and the enlarged setae on either side of the ventral median line, were sufficient at that time to fully differentiate the species. Subsequently one of us received and described 2 some specimens of an earthworm belonging to this same genus also from the Philippine Islands ; they were referred to the same species, though the entire absence of spermathecae was noted. Upon this latter point Perrier made no observations. It was therefore concluded that it would be better to regard the worms described as being of a different species. In the ' Monograph of the Oligochaeta' therefore they were described under the name of Perichceta acystis. Since then Michaelsen3 has re-described Perichceta biserialis very fully, and more recently still Dr. Horst4. Dr. Horst, whose observations where published after ours were made, examined eight mature worms from Paramaribo in Dutch Surinam : " of these two have four pairs of copulatory papillae on 1 " Sur les Vers de terre des Philippines et de la Cochinchine," Comptes Rendus, 1875, p. 1043. . . 2 F. E. Beddard, "Observations upon an American species ot Perichceta, &c.," P. Z. S. 1890, p. 63. 3 " Die Terricolen des madagassischen Inselgebiets,' Abh. Senck. nat. Gres. xxxi. (1897) p. 226. * " On the Variability of Characters in Penchaetidae, Notes Leyd. Mus. xx, p. 201. |