ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 33 



of the nucleus. They are also devoured by leucocytes in the parenchyma. 

 The development of leucocytes is like that in Mammals. 



The bird's red blood corpuscles are flat bi-convex discs, gradually 

 pointed at the ends. They are larger in the larger birds. They vary 

 in number from 1,715,000 to 5,400,000 per cubic centimetre, tending to 

 be more numerous when they are small. 



Ossification in Amphibians.* — J. H. Klintz finds that enchondral 

 ossification, familiar in Amniota, occurs also in Salamandra maculosa. 

 It will be remembered that perichondral or periosteal bony tissue, which 

 is applied directly to the cartilage of a long bone, arises from the peri- 

 chondrum, i.e. a layer of connective-tissue surrounding the cartilage. 

 By continued deposition of new bony tissue on the shaft the bone grows 

 in thickness and at its two ends, leaving at a later stage only the two 

 cartilaginous ends free. But enchondral ossification arises internally. 

 After tlie periosteal ossification has made progress the cartilage in the 

 shaft begins to show medullary cavities, blood-vessels, and osteogenetic 

 tissue. The osteoblasts lining the cavities form bone lamellae. The 

 author's question is as to the phylogenetic beginning of the enchondral 

 mode of ossification. He finds that what occurs in the salamander is 

 quite different from that which he has studied in fishes, and like that of 

 higher Vertebrates. But the epiphyse3 do not ossify. They remain 

 either hyaline cartilage or become calcified. 



Red Blood-corpuscles of Amphibians-f — Fr. Meves discusses in 

 detail the peripheral band (Randreifen). This is not an external mem- 

 brane nor the peripheral zone of the cytoplasm. It is a definite structure 

 which may be isolated, it has a fibrillar structure and associated granules, 

 it has transverse membranes wliich perhaps represent transverse anasto- 

 mosis of the fibrils, it is a firm elastic structure which conditions the 

 form of the red blood-corpuscles. 



According to Meves there is no external membrane. Internal threads 

 and granules are described, but the reality of two concentric zones is 

 denied. An account is given of the change in form exhibited in the 

 fresh blood and under the influence of reagents. 



Nuclear Division in Blood-corpuscles of Salamander.^ — Paolo 

 della Yalle describes peculiar division-phenomena w^hich occur in the red 

 blood-corpuscles in the larvae of Salamandra maculosa. The most 

 marked feature is a progressive increase in the number of chromatin 

 elements and a correlated diminution in their size. There is here a link 

 between karyokinetic and amitotic division. Longitudinal division of 

 the chromosomes is shown not to be a necessary phenomenon in nuclear 

 division. The continuity of the diverse forms of nuclear division con- 

 firms the view that the chromosomes are not more than temporary and 

 variable aggregations of the chromatin. 



Distribution of Cutaneous Glands in Amphibia.§ — Marie Phisalix 

 finds that the two kinds of permanent skin-glands in Amphibians are 



* Arbeit. Zcol. Inst. Univ. Wien, xix. (1911) pp. 165-94 (2 pis. and 2 figs.). 



t Arch. Mikr. Anat., Ixxvii. (1911) pp. 465-540 (3 pis. and 52 figs.). 



X Archivio Zoologico Napoli, v. (1911) pp. 119-200 (2 pis.). 



§ Ann. Sci. Nat. (Zool.) xii. (1910) pp. 183-201 (9 pis.). 



Feb. 21st, 1912 D 



