THE LEECHES OF THE U. S. NATIONAL MUSEUM. By J. Percy Moore, . Instructor in Zoology, Univo'sity of Pennsylvania. Through the courtesy of the curators the collection of leeches con-tained in the U. S. National Museum has been placed in my hands for study and determination. Though small, and much of it poorly pre-served, the collection has proved an interesting one. None of the forms had previously been identified; several have been found to be unde-scribed, several others have been mentioned in the literature but once or twice, and many are here recorded from new localities more or less remote from those previously known. The material has been drawn from various parts of the world, but it is to be regretted that our own American leeches are so poorly represented. Our fauna is a rich one, but is, perhaps, well known to but one person, who has as yet shared but little of his knowledge with the scientific public. We are still in nearly complete ignorance of the number and distribution of the species, and many interesting morphological questions remain to be elucidated. But one attempt has been made to systematize our knowledge — that of Prof. A. E. Yerrill twenty-five years ago — and that upon very inade-quate material from comparatively few localities. It is to be hoped that a greater interest will be taken in making well-preserved collec-tions, and that our National Museum will soon have gathered together a complete series, not alone of leeches, but of annelids generally and other worms as well. This is perhaps not the most suitable occasion to enter upon a dis-cussion of any of the broader or more theoretical problems of morphol-ogy upon which the collection throws light. There is, however, one matter of especial interest to the systematic student to which some reference may profitably be made. I refer to the annulation of the somite. My observations on this subject accord perfectly with the views exi)ressed by Whitman (5 and 6) and later by Lang (4) and Blanchard for the Glossiphonidte, Hirudinidffi, and Herpobdellidse, and I am pleased to be able to extend them to the Ichthyobdellidae also, which has, I believe, not previously been done. Apathy (1), who has made the most important recent contributions to the external morphol-ogy of the latter family, takes a precisely opposite view to that of Proceedings U. S. National Museum, Vol. XXI— No. 1 160. 543
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