ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 301 



Pigmentation of the Human Iris.*— A. Rudolf Galloway traverses 

 the conclusions of C. C. Hurst as to the pigmentation of the human iris 

 and the Mendelian inheritance of the types. The human iris cannot be 

 held to coDsist merely of an anterior and a posterior surface, each, in 

 certain eyes, exhibiting its own kind of pigment. The stroma may 

 contain pigment cells, more especially in its deeper parts, and granular 

 pigment towards the anterior surface. Pure blue, or so-called " simplex " 

 eyes, which to any outward examination appear free from anterior 

 pigmentation, may show stroma pigment cells and anterior granular 

 pigmentation when examined microscopically. Hence the classification 

 of " duplex " and " simplex " eyes is erroneous, and there is no dis- 

 continuity or Mendelian inheritance between them. 



Minute Structure of Epiphysis in Opossum.f — H. E. Jordan finds 

 that the epiphysis is simple in the opossum. It is a shallow tubular 

 evagination of variable degree from the inter-commissural portion of the 

 roof of the third venticle. It looks as if it were in a state of arrested 

 development, and is very variable in detail. It typically consists of a 

 syncytial neuroglia framework, in the meshes of which are scattered more 

 or less highly differentiated or modified ependymal cells, and of delicate 

 bundles of nerve-fibres. Histologically considered, it seems to be primi- 

 tive or rudimentary, and in a condition of instability. There is nothing 

 to suggest that it is important in metabolism. 



Innervation of the Heart. | — Sergius Michailow gives a very detailed 

 account of the nerves of the pericardium, epicardium, myocardium, endo- 

 cardium, and blood-vessels of the heart. The various plexuses, the 

 motor and sensory nerve-endings, and the ganglion-cells of the heart are 

 minutely described. 



Bone of Ox Heart. § — E. Retterer and A. Lelievre have enquired 

 into the structure and development of the bone in the ox heart. 

 It was discovered by Aristotle, and Daubenton showed (about 1750) that 

 there are two. The authors have found another in the sheep. Along 

 the adherent margin of the right and left sigmoid valves of the aorta 

 there appear one or two nodules of a cartilaginous consistence, but of a 

 vesiculo-fibrous structure. These nodules are subsequently transformed, 

 at least in their central portion, into bony tissue, which exhibits Dhe two 

 characteristic stages of bone-development. 



Formation of Intracellular Crystals in Hepatic Cell.|i— A. Policard 

 has studied the role of the mitochondrial apparatus of the hepatic cell in 

 forming crystals. They sometimes retain the flexuose shape of the chon- 

 drioconts which produce them. Their formation is analogous to the 

 formation of pigment-crystalloids by chromoplasts in certain plants. It 

 is interesting to notice the multiple functions of mitochondria, which 



* Biometrika, viii. (1912) pp. 267-79 (1 pi). 



t Anat. Record, v. (1911) pp. 325-38 (IS figs.). 



t Zeitschr. wiss. Zool., xcix. (1912) pp. 539-687 (5 pis. and 8 figs.). 



§ C.R. Soc. Biol. Paris. Ixxii. (1912) pp. 371-3. 



II C.R. Soc. Biol. Paris, Ixxii. (1912) pp. 91-3. 



