Histology and Cytochemistry of Skin Gland Areas in the Caribou, Rangifer

Abstract

The microscopic structure and glandular cytochemistry of three specialized cutaneous areas in the caribou form the subject of this report. These are the tarsal gland area, the interdigital gland areas and the preorbital pocket. Their location and gross structure may be seen in Plate I. These structures have been shown to vary in their presence and structure among artiodactyls, and have been most recently reviewed by Schaffer (1940). There is still much, however, that is unknown concerning them, particularly regarding seasonal and sexual variation and microscopic structure and chemistry of the glands. It is hoped that this report will help fill these deficiencies for the caribou, and provide significant information for behavioristic and phylogenic studies as well as for comparative glandular cytology and cytochemistry. I am very grateful to Ralph S. Palmer for obtaining and providing the skin samples upon which this study is based. Financial support for publication was provided by funds derived from income on the endowment of the Horace H. Rackham School of Graduate Studies, University of Michigan. This study is based upon skin samples from an adult male and an adult female, both shot at Anaktuvik Pass, Brooks Range, Alaska on April 3, 1950. The skin samples were fixed in a formalin-alcohol mixture and were later stored in 70 per cent alcohol. Blocks of tissue, the locations of which are indicated in Plate I, were cut from the samples, washed, dehydrated through a series of ethanol solutions to benzene, and embedded in paraffin. Serial sections 10 microns in thickness were treated by the following techniques. (1) Ehrlich's acid hematoxylin and eosin Y (Bensley and Bensley, 1938). (2) Taenzer-Unna acid orcein method for elastic fibers (Lillie, 1948. The orcein, dissolved in 70 per cent ethanol was used at room temperature. Azure II (Nat. Aniline …