On the Nomenclature of Echinoids. 117 22. x. 1890 (Lt.-Col. Yerbury) ; and one <$ from Colombo, Ceylon, October 1898 (E. E. Green). The types of both sexes are in the British Museum (Natural History). Writing on November 1st, 1909, with reference to Musca pattoni, Captain Patton said : — " This species breeds in cow-dung, and its pupa is dirty white. The fly has peculiar habits, in that it sucks the blood which oozes from the bites inflicted on cattle by Hcematopota and other Tabanids, Stomo.vys, and Philtematomyia. It likewise sucks the juice out of the vaccine vesicles on calves, and also the blood after the vesicles are scraped." From Musca domestica, L. (syn. M. determinata, Walk.), M. pattoni can be distinguished, inter alia, by its usu illy larger size, stouter habit of body, much narrower front in the male, the greater breadth of the sides of the front in the female, and the more sharply defined median stripe on the abdomen in both sexes. The fact that the first segment of the abdomen is in both sexes for the most part ochraceous-buff or buff, instead of entirely or for the most part black or bronze-black, will serve to distinguish Musca pattoni from M. corvina, Fabr., and other species closely allied thereto. From Musca nebulo, Fabr., — which, according to Captain Patton, is "the common Musca of Madras, breeds in horse-dung and other refuse, particularly in night-soil, and has a reddish-brown pupa," — M. pattoni differs, inter alia, in its much larger size, in the front of the male being only half or less than half as wide, and in the presence of the clove-brown mark on the apex of the fourth abdominal segment. In M. nebulo the fourth segment of the abdomen, or at least its apex, is entirely pale. XVI. — On some Points in the Nomenclature of Echinoids. By Dr. Th. Mortensen. The nomenclature of Echinoids has received considerable attention of late years, and a great number of publications dealing more oi less extensively with problems relating thereto have appeared. Unfortunately the result of these discussions has been by no means a general agieament on these questions among specialists. It is true that recently most of the authors seem to have come to an agreement on some important points; but now Lambert and Thierj, in their ' Essai de nomenclature raisonnee des Echinides ' and
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