ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 37 



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Membranes of Notochord in Cyclostomes and Fishes.* — 0. 

 Schneider finds that the elastica interna is almost always present. It 

 is usually a fenestrated membrane with predominantly longitudinal 

 meshes, within which there is a reticulum of thinner and irregular fibres. 

 In Cyclostomes it is not coherent or separable, but a membrane is hinted 

 at in the occasional union of individual fibrils. 



The elastica interna reaches its highest differentiation in the inter- 

 vertebral region of Selachians. In sturgeons it extends all along the 

 vertebral column. In Teleostsit is usually confined to the intervertebral 

 regions. 



In the fibrous sheath, in the vicinity both of the elastica interna and 

 of the elastica externa, there are often elements of an elastic nature. 

 These are short fibrils or spindle-shaped strands in Cyclostomes and 

 Selachians and some Teleosts, but in most Teleosts and in Ganoids a 

 network may be formed. There are cellular elements in the fibrous 

 sheath of sturgeons. It is probable that both elastica interna and 

 elastica externa arise directly from the notochord epithelium. 



Stroma of Suprarenal Cortex.t — P. Snessarew describes in the 

 cortical region of the suprarenal bodies a very fine fibrillar connective- 

 tissue reticulum, which appears to have at once a supporting and an 

 isolating function. 



Double Innervation of Striped Muscle. J — J. Boeke finds that 

 striped muscle is innervated by two independent hypolemmal nerve- 

 endings — motor and sympathetic, the latter probably being a tonus- 

 innervation. The sensory nerve-endings are always epilemmal ; the 

 other two are hypolemmal. 



Mitochondria in Adult Nerve-cells.§ — J. J. Schirokogoroff refers 

 to the fact that most investigators of nerve-cells doubt the presence of 

 mitochondria in the cells of the central nervous system of adult warm- 

 blooded animals. By using special methods he has convinced himself of 

 the presence of mitochondria in all the ganglion cells of the rabbit's 

 central nervous system. He has also seen mitochondria in the nerve- 

 cells of the retina. 



Glans-penis of Felidge.|| — E. Retterer and H. Neuville have studied 

 the minute structure of the glans-penis in lion, tiger, panther, leopard, 

 serval, etc. In spite of its conical shape, the glans of Felidte is homo- 

 logous with that of man, dog, and horse. It consists essentially of a 

 prolongation of the corpora cavernosa which are at first erectile and 

 adipose, but become eventually bony. In all the feline race, the 

 " balanic " mucosa bears projecting papillae which have at the base of 

 the glans a corneous covering and represent organs of sexual excitation. 



* Zool. Jahrb., xxxvi. (1913) pp. 171-214 (7 pis.). 



t Arch. Mikr. Anat., lxxxii. (1913) lte Abt., pp. 408-13 (3 figs.). 



j Anat. Anzeig., xliv. (1913) pp. 343-6 (10 figs.). 



§ Anat. Anzeig., xliii. (1913) pp. 522-4 (1 pi.). 



|| C.R. Soc. Biol. Paris, Ixxv. (1913) pp. 314-17. 



