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Show 610 MR. F. E. BEDDARD ON THE [May 22, The large number of reputed species of this genus is due to two principal causes. In the first place, it has been tacitly assumed that a Perichceta coming from the N e w World would be certainly different from an Eastern form. W e now know that this is not the case, and that in all probability there are no indigenous species outside of the Malayan Archipelago and the adjacent parts of the Asiatic mainland. In the second place, sufficient attention has not been paid in the past to the great variability which is found among the species of this genus. I direct particular attention as regards this matter to the large series of variations seen in such a protean species as Amyntas hawayanus or A. stelleri. Gradated specimens connect the extreme forms which, when described singly, have been referred to different species, a quite necessary conclusion in view of the facts then known. I have naturally, therefore, found great difficulty in deciding upon the value of specific characters in the following survey of the species of the genus. There are some characters which seem to be of first class importance and to be not subject to variation. Those characters are:-(1) Tbe setae on the clitellum, when these are present on every segment and form continuous rows. Otherwise, in those cases, such as A. hawayanus, where the setae are at best but few, they vary in number and in the segments upon which they occur. In such forms as A. violaceus, A. taprobance, there is no variation. (2) The presence or absence of a rounded muscular sac, often containing a protrusible penis, into which the duct of the spermiducal gland opens. This is either present or absent in a given species, definitely present or absent. (3) The caeca again seem to be always either present (in the majority of cases) or absent, with the apparent exception (?) of A. merabahensis. (4) The spermathecae again are, with not many exceptions, constant in number of pairs and position of segments. In one or two instances (A. dyeri) their very dorsal position seems to be a valid specific difference. (5) The close approximation of the male pores in a few species (e. g., A. iris, A. halmaherce) is a good character. But a slight difference in the remoteness of the two pores must be used with the greatest care, if at all. I have not made use of it here, as I a m not convinced that it is possible to eliminate from such slight differences the effects of differing degree of contraction. (6) The position of the last "heart"; this is always in segment xii. (A. taprobance) or in xiii. (the vast majority of species). The only species which varies at all is A. stelleri. (7) The presence or absence of septa in the segments occupied by the gizzard. As a rule those septa (viii./ix., ix./x.) appear to be absent. But in some species, one or both are present and even quite thick. In other cases, there is one very thin septum or not more than traces. The character must therefore be used with great care: its use is marred by the fact that there are not always exact observations upon the point on record. (8) Rarely, e.g. A.neoguinensis,the testes, funnels,and sperm-sacs are present to the number of one pair only. This seems to be a non-variable characteristic of those species in which it is met with. (9) The |