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Show Oreohelix howardi, new species Dr. David T. Jones! Recent investigation on the embyronic whorls of western Oreohelices has established the usefulness of this and other minute details as criteria in separating the aggregations in our different canyons, which have, in general, gone indiscriminately under the name deptesse (Cockerell). Inasmuch as these aggre,., gations are natural units, isolated to a great degree from similar units in neighboring canyons by desert stretches, it appears that recognition and study of at least the more outstanding of such units, will aid in the understanding of variation in the genus Oreohelix, I have long admired such a natural aggregation in Mill Creek Canyon near Salt Lake City. For nomenclatural simplicity, I am here describing it as a species, though the taxonomists are welcome to place it where they wish. At this time, however, we are far more interested in securing the natural story from the specimens and Field data, than in arguing taxonomic status. I have been aided in this study by collections taken over a number of years which are now in the Invertebrate Museum of the University of Utah. Recent extensive collections at Church Fork by Doris Tippit have also contributed much. Notes on de tails similar to those given below on howardi can be found for the Colorado depresse and for our cernee in a neighboring canyon, in Pilsbry's recent article (1939, Land Mollusca of North America, A.N .S.P., Monograph 3, Vol. 1, Part 1, Philadelphia). In order to eliminate needless repetition we have tried also to conform to this article in descriptive names, numbering of whorls, and in measurements. Variation is shown on the drawing by dotted lines. In the plate accompanying this article, fig. 1 is a detail of the first embryonic whorl; fig. B, a sketch -of the embryonic shell and its variations in size; fig. C, an apical view of a large shell (much of the detail in this drawing has been taken from the holotype); fig. D, a basal view of a large shell; and fig. E, apertural Views of one various sizes of shells. Oteohelix howardi n. sp. This is the common Oreohelix found in Mill Creek Canyon and its branches. The species is named for Dr. Orson Howard, former head of the. Dept. of Zoology in the early days of the University of Utah. Later, for a long series of years he served as curator of the Museum of Zoology. lDepartment of Biology, University of Utah, Salt Lake City, Utah. Volume 21, Proceedings of the Utah Academy of 'Sciences, Arts and Letters 61 |
