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Show 686 MR. F. E. BEDDARD ON N E W [Dec. 20, finds that in his species the gizzard is a mere rudiment in the fourteenth segment, in front of which (in segment xiii.) are a pair of calciferous glands not refered to by Perrier. In all these points, with one exception, m y " Perionyx excavatus" agrees with Michaelsen's species ; I can distinguish no marked difference of any kind between these worms, except in size, and the size is after all not so marked as to lead to the opinion that it is an index of specific distinction-110 m m . as compared to 85 m m . In the more detailed description which follows of the male pores there may indeed appear to be a little difference, but I am uncertain how far to refer this to defective preservation of the P.gruenewaldi. The exception to which I have referred concerns the gizzard; this organ in the worms examined by myself and referred to Perrier's P. excavatus is rudimentary indeed, but such as it is it appears to lie in the sixth segment, as it does in the two other species to be described presently. Rosa gives some account of a worm from Burmah1 which he identifies with Perionyx excavatus of Perrier; he points out that the gizzard is situated anteriorly, and not, as Perrier stated, in the xiith segment; Rosa, however, makes no mention of the calciferous glands, nor of the genital setae. The description of the male pores agrees with Perrier's description and with the appearance of these pores in the worms which I am disposed to identify with Perrier's Perionyx excavatus, A very characteristic feature of the latter was the absence of any diverticulum of the spermatotheca; with regard to Perionyx excavatus Perrier remarks (loc. cit. p. 129), "les poches copulatrices sont situees dans les anneaux sept et huit; elles m'ont paru formees d'un simple sac piriforme." I take it that this sentence implies the absence of any diverticula. On the other hand, Michaelsen refers to diverticula in his Perionyx gruenewaldi and P. sansibaricus. This seems, at any rate, to be a good distinction between the two species. I have received from Seebpore examples of a species of Perionyx which appears to be different from Perionyx excavatus ; it is certainly different from the worms identified as such by myself; but as Perrier's account is incomplete in one or two points, it is a little difficult to be absolutely certain. These examples were rather stouter in build than the Manila worms, and the coloration was a little less marked; this, however, may be the effect of the corrosive sublimate used in the preparation of them. In the internal anatomy this species is to be distinguished by five differences from the Manila species ; these are as follows .- The gizzard is fairly well marked and lies in the vith segment; there are no calciferous glands at all, though the oesophagus is somewhat folded and vascular posteriorly. The last pair of hearts lie in tbe xiiith segment; in the form from Manila the twelfth segment is the last which contains a pair of hearts; nothing is said upon this point by either Perrier or Rosa. The spermatothecae are, as in the other species (excepting P. sansibaricus), two pairs and they 1 Loc. cit. |
