ZOOLOGY 571 



brane of the branchial tree. Of this membrane, he states 

 that " it is by far the most efficient part of the recoil mechanism 

 of the branchial tree, and is a very important, if not the most 

 important, part of the recoil mechanism of the entire lung." 

 (" A Note on the Elastic Membrane of the Bronchial Tree of 

 Mammals, with an Interpretation of its Functional Significance," 

 Anat. Rec, vol. xxiv. No. 3, Oct. 1922). 



J. Thornton Carter has investigated the microscopic struc- 

 ture of the enamel of the teeth of the Primates and other 

 Mammals (" On the Structure of the Enamel in the Primates 

 and some other Mammals," Proc. Zool. Soc. Lond., Part III, 

 1922). He finds that the enamel pattern affords a useful 

 test of affinity if taken in conjunction with the character of 

 the tube-penetration, and enables one to discriminate between 

 Multituberculates, Marsupials, and Placentals. 



A joint paper by P. N. Johnstone, F. H. Wakefield, and 

 H. M. Currey is devoted to a comparison of the vascularity 

 of the Purkinje fibres and of the heart muscle of the calf 

 (" On the Comparative Vascularity of Heart Muscle and of the 

 Purkinje Fibers," Anat. Rec, vol. xxiv. No. 2, Sept. 1922). 

 The vascular supply of the Purkinje fibres is very scanty in 

 comparison with the heart muscle. The writers suggest that 

 these fibres do not represent tissue specialised for the same 

 type of contractility as heart muscle. 



Other papers include : 



Agduhr, E., " Einige wahrscheinlich bisher unbekannte, teils im Ependym 

 gelegene, teils in die Fossa rhomboidea hineinragende Nervenendi- 

 gungen," Acta Zoologica, No. i, 1922. 



Drahn, F., " Ueber den histologischen Bau der Gleitsehne des Muse, biceps 

 brachiibeim Pferd," Archiv fur mikroskop. Anat., vol. xcvi. No. i, 1922. 



Embryology. — The development of the sex organs of the 

 mollusc Limax maximus L. has been worked out by H. 

 Hoffmann (" Hber die Entwicklung der Geschlechtsorgane bei 

 Limax maximus L.," Zeit. fiir Wiss. Zool., vol. cxc. No. 4, 

 1922). All the genital organs arise from an ingrowth of the 

 ectoderm at the posterior end of the mantle cavity. The 

 anlage develops first, when the common anlage of the heart, 

 pericardium, and kidney has separated into its single con- 

 stituent parts. No connection exists between the anlage of 

 the sexual organs and the common anlage of the heart, peri- 

 cardium, and kidney. The hermaphrodite gland develops the 

 earliest, out of an enlargement of the proximal ends of the 

 primary genital ducts. The proximal half of this duct remains 

 thin and represents the hermaphrodite duct ; the distal half, 

 however, enlarges and becomes the sperm-oviduct which 

 distally is separated into two distinct ducts. 



G. S. Sansom contributes to the Journal of Anatomy (vol. Ivi, 



