Journal of Applied Microscopy. *255 



ANIMAL BIOLOGY. 



Agnes M. Claypole. 



Separates of papers and books on animal biology should be sent for review to 



Agnes M. Claypole, Sage College, 



Ithaca, N. Y. 



CURRENT LITERATURE. 



Leidig, F. Vascular Epithelium. Arch. fr. Capillaries have been recently shown 

 Mikr. Anat. 52: 1898, pp. 152-155. ^y Maurer to exist in the buccal epi- 



thelium of amphibia. Leidig noticed such in his work, " Die Zelle iind Gewebe " 

 (1885). He now calls attention to the existence of vascular epithelium in the 

 earthworm and leach, and quotes the observations of various investigators on 

 the subject. The superficial emergence of blood vessels is important in refer- 

 ence to the respiratory functions of the animals. A. M. c. 



Gardner, M. Histogenesis of Elastic Tissue. From Studies in the amniotic mem- 

 Le Physiologiste Russe, 1898, pp. 3-14. branes of various mammals, the author 



reaches the following conclusions : 1. The elastic substance forms centrally in 

 the protoplasm of cells, in granules. 



2. The granules fuse and form delicate filaments, and this fusion may occur 

 in the limits of one, all, or in several anastomosed cells. The nucleus plays no 

 part, so far as known, in the formation or fusion of granules ; this is probably a 

 cytoplasmic process. 



3. Delicate elastic filaments of adjacent cells fuse and form larger filaments, 

 these form similar filaments, and together they form a larger fiber. 



4. No active intrusion of elastic filaments into extra protoplasmic substance 

 is observable. The formative cells determine the final recticular or fibrous struc- 

 ture. Nothing is said of the fate of the nucleus of the cell-forming fibers. 



A. M. C 



Braehet.D.A. Researches on the Development The results of the investigations are 

 of the Heart and Great Vessels and the ^ ^ 1 • ^1 r n 

 Blood in Urodel Amphibians (Triton alpes- stated m the foUowmg summary : 

 tris). Archiv d'Anatomie Microscopique, 2, 1. The elements at whose expense 



ascicu e, _, 9 , pp. 534- ^j^^ ^^.^^ rough outline of the heart and 



great vessels of the embryo are made are not migratory cells, which become 



masked at the point of the differentiation of the organ. 



2. The heart and primary vessels have in Triton an origin clearly and exclu- 

 sively hypoblastic. 



3. The development is absolutely independent of that of the red blood cells 

 as at one time they are hollow and empty; only secondarily, after they become 

 connected with the blood islands, do they become filled with blood. 



4. The blood has its origin at the cost of the yolk hypoblast, in a well defined 

 region that is called the medio-ventral blood islet and its two branches of bifur- 

 cation. In the Triton this islet is the only spot of formation of the blood cells. 



The following facts are shown by the author to be of great significance : 

 Goette twenty-five years ago maintained that it was possible to establish a com- 

 parison between the vascular yolk structures of amphibians and of those vertebrates 



