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Show 52 MR. F. E. BEDDARD ON [Feb. 4, 3. Observations upon an American Species of Perichata, and upon some other Members of the Genus. By F R A NK E. BEDDARD, M.A., Prosector to the Society. [Eeceived December 23, 1889.] (Plates IV. & V.) Some weeks since Mr. C. Bartlett brought me two living earthworms, which he had found in earth surrounding the roots of an orchid, received from South America. One of these was a very small example of a Lumbricus, which I have not yet identified ; the other was a Perichceta, which is illustrated in the accompanying coloured sketch (Plate IV. fig. 1). There are so very few coloured figures extant of foreign earthworms1 that I have considered it desirable to put on record the coloration of this species, which appears to be P. indica. The worm is remarkable for its extreme activity, as has been already noted by Baird (1) and by Perrier (18) in other species of Perichceta, studied in the living condition. Another curious characteristic of the worm is its metbod of progression ; many Oligochseta seem to make use of the mouth in locomotion, attaching themselves firmly by it, while the following segments are moved forwards; in the present species a considerable portion (? the whole ) of the buccal cavity is everted whenever the animal moves, so that the head has a remarkably leech-like aspect. I have attempted to illustrate the appearance of the anterior end of the body during locomotion in the accompanying drawings (Plate IV. figs. 2, 3). I never observed the worm in motion without this alternate eversion and inversion of the buccal cavity. As will be seen, the colour of the worm is a rich brown, somewhat darker upon the clitellum, with a whitish line in the middle of each segment. The colour appears to be caused by at least two distinct pigments; one or more of these is dissolved out bv alcohol, leaving the worm colourless, except for a dark bluish-brown area along the back (which resists the action of the spirit), and is recognizable in sections as black granules lying in the epidermis and in the circular muscular layer. I lay particular stress upon this fact, for the reason that in other specimens of P. indica (see no. 5), which I received from New Caledonia and which were sent to me in alcohol, the brown coloration and the whitish line in the middle of each segment are preserved. It is interesting to find that P. indica, which has been already recorded from the East Indies and from New Caledonia occurs also in South America. There are not many species which have so wide a distribution; P. affinis, P. houlleti, and Urochceta corethrurus, however, are forms which inhabit the tropics of both the 1 The only coloured figures known to m e (taken from life) are several of Perichceta and Hypogmon by Schmarda (20), and of Microchceta rappii in a paper by myself upon the anatomy of this worm (3); Schmarda's figures lose some of their value from the fact that they are not accompanied by any description of the internal characters, and cannot, therefore, be easily identified. |