No abstract

The natural history of Sceloporus magister was studied in popu lations at tlie Nevada Test Site, Mercury. Individuals were marked and kep under surveillance from 1965 through 1970. Reproductive cycles were examine by field observation and by autopsy. Hatchlings appear in the population in Jul; and August. Growth is rapid for the first year. Sexual maturity is reached befor the second hibernation or soon after emergence from it. Territoriality is a pre nounced behaviorism; individuals have been observed to remain in a small are for several years. Food consists of arthropods, with ants the predominant iterr Reproduction occurs during May and/or June with only one clutch per yeai Density is variable and depends on the appropriateness of the habitat.GREAT BASIN NATURALIST Vol. 33, No.the Nevada test site, Nye County, Nevada." The Great Basin naturalist 33, 133-146.

No abstract

There are many descriptions in the literature on cattle of asymmetrical, acardiac twins to otherwise normal animals, or diprosopus in However. it is unfortunate that published reports of embryonic duplications are generally limited to a description of external gross features of the animals. This study presents a description of how deep tissues respond to abnormal duplication of peripheral areas, and particularly how morphologically asymmetrical parts of a system which develop from symmetrical primordia are altered when confronted by demands of a duplication of the head area.A necropsy was done on a diplopagus Hereford stillborn calf which was procured near Wichita, Sedgwick County, Kansas. This specimen would be classified as diplopagi, type AIII,6 representing a double monster in whch two completely separated heads are present, each being equal to and the symmetrical equivalent of the other. Each of the complete and normally proportioned heads articulated with a separate, but laterally-torqued, atlas vertebra, which in turn joined with one of the two anterior faces of a three-faceted second cervical vertebra. Within this modified axis vertebra, a Y-shaped channel allowed the bifurcating spinal cord to pass.In the specimen studied, normal development of the circulatory system from the symmetrical embryonic pattern was altered in response to the duplicated condition cranially. The paired primordia of the heart, which would fuse in normal embryonic development, remained partially separate. An anomalous cardiac complex developed instead; it consisted of a larger right heart and a smaller left heart, each with incompletely partitioned atria, but separate ventricles. The arteries and veins cranial to the heart also retained much of their embryological symmetry of form, resulting in a relatively normal circulatory pattern within each head.The cardiac tissue of this calf appeared as two conjoined hearts connected through the atria and part of their ventricles ( fig. 1). The right heart was larger than the left (length and width: 8.0 cm X 7.5 cm and 6.0 cm X 5.0 cm, respectively), and they were separated at the ventricular apex for 2.5 cm. In the small left heart, the ventricle partitioning was incomplete, as there was a large interventricular foramen which allowed communication between pulmonary and systemic circulations ( fig. 2). The aorta was attached to the right side of the cranial end, and received blood directly from the left ventricle and from the diminutive right ventricle through the opening in the interventricular septum. A small pulmonary artery exited from the right ventricle.The right heart consisted of a large, undivided ventricle an aorta and a pulmonary artery ( fig. 3). The aortic arches from each heart joined before continuing as a single abdominal aorta. Each head was supplied blood via two common carotid arteries. The right and left common carotid arteries of the right head arose from a short brachiocephalic trunk, and the distal course and tributaries of each appeared normal in that head. A third ...