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Show 664 DR. A. G. BOURNE ON INDIAN EARTHWORMS. [D numerous forms which I have called Perichceta it extends in many forms (as in P. armata, Bedd.) over four somites, and in one form over five somites instead of three. So, as they stand, these generic distinctions seem to me to be of little value. I am, however, inclined to hope that a careful anatomical study in the fresh state of the large variety of forms which I have already discovered (I have, moreover, every reason to believe that the field is as yet by no means exhausted1) will enable m e to group these very interesting forms in a more rational manner. I do not think that the classification suggested by Benham2 will turn out to be a very natural one. I refrain, however, from making any suggestions myself in this preliminary note, as I expect that the natural classification will have to be based upon the result of very careful examination of a very large number of fresh forms. I shall doubtless be able ere long to go to Ceylon, Burmah, Java, and other places, and compare fresh specimens of the forms which have been described from these regions with m y Indian species. I have in the present note spoken of all the forms as Perichceta, with the exception of Perionyx saltans, although I believe that the differences have in many cases a full generic value. A glance at m y tabular statement (p. 665) will show what great differences exist. PERICH^TA LAWSONI, sp. n. The clitellum extends over somites xiv., xv., xvi., and xvii., but is very slightly marked. Even in adult specimens it requires careful examination to detect any external difference between these somites and the ordinary somites of the body. There is, however, no doubt as to its existence and extent in either this or the following species, P. bivaginata. The male pores are placed on somite xviii. There are no papillae. The oviducts open separately, although very near the median line, in somite xiv. There are two pairs of spermathecae; these are placed in somites viii. and ix. The spermathecal pores open between somites vii. and viii., and viii. and ix., respectively. I have found no nephridia. The gizzard is situated in somite x. Intestinal caeca are present in somite xxvi. and run forward to somite xxiii. There are from 30-35 setae in each somite, which are arranged so as to leave small gaps in the median, dorsal, and ventral line. The ventral gap is equivalent to about two ordinary gaps, and the dorsal gap to about three ordinary gaps. The setae are present ou the clitellar somites and are arranged as in the other somites. No modified genital setae were observed. Length 250 millim., circumference 7 m m . ; number of somites 119. Hab. Ootacamund, Nilgiris, at an elevation of about 7000 feet. # 1 In tbe one week which I recently spent in tbe Salem and Yercaud district, it will be seen that I discovered three new species of Perichata, besides other forms. 2 Quart. Journ. Microsc. Sci. vol. xxvi. n. s. p. 225. |
