160 SUMMAKY OF CURRENT RESEARCHES RELATING TO 



Phenomena of surface-tension and absorption play an important part 

 in the differentiation. 



Histological Peculiarities of Turtle.* — K. Ogushi describes the 

 vascularization in the villi of the buccal, pharyngeal, and oesophageal 

 epithelium in Trionyx japonicas, which have a respiratory function. 

 As Agassiz pointed out, there is also a very abundant ramification of 

 blood-vessels on the skin of the lower surface, and this is also of 

 respiratory significance. The author also describes a nerve-ending 

 beneath a papilla on the lip, and the peculiar structure of the epithelium 

 of the epididymis. 



Development of Cartilage of Notochord in Lizards. f — J. Pusanow 

 goes back to the stage when the notochord consists of a vacuolated 

 syncytium without even a chorda-epithelium. There is active amitotic 

 division of the nuclei ; no penetration of ectochordal cells was seen ; 

 there is a chondro-mucoid metaplasis of the " chorda-membranes " 

 which are formed between the vacuoles ; a differentiation of a ground- 

 substance or exoplasma and an active endoplasma occurs ; the nuclei 

 increase in size as the ground-substance increases, and thereafter they 

 get smaller again ; a hyaline cartilage is formed which very soon 

 undergoes degeneration till only a vestige remains. The spot where 

 the chorda cartilage appears is the spot where the vertebra afterwards 

 breaks across in autotomy. 



Leucocytes of Amblystoma.J — Hal Downey finds that the poly- 

 morphonuclear leucocytes of this Amphibian contain granules with the 

 general character and staining reactions of azurophil granules. They 

 are quite variable in size, number, and distribution. In this respect they 

 resemble the azurophil granules of the mammalian lymphoid cells, but 

 their radial grouping around the centrosphere, their constant appearance 

 in the polymorphonuclears, and their great number in any one cell, place 

 them nearer the " special " granules of the higher animals. 



The lymphocytes of most Amphibia (frog, Cryptobranchus, etc.) 

 lose their azurophil granules when they differentiate into polymorpho- 

 nuclears, and their cytoplasm becomes oxyphilic. In Amblystoma the 

 cytoplasm of the polymorphonuclears remains " lymphoid " in character, 

 while the azurophil granules remain and their number is increased. 

 This may be regarded as an attempt towards the differentiation of a 

 " special " granulation. 



In Amblystoma all possible intermediate stages between larger 

 lymphocytes and polymorphonuclears are found in the circulating blood. 

 The " parachromatin canals " of Werzberg are optical appearances due 

 to deep furrows on the surface of the nuclei. The erythrocyte nuclei 

 of Amblystoma are more pyknotic and more degenerative in character 

 than those of the erythrocytes of the garter snake, and Minot's distinc- 

 tion of ichthyoid and sauroid types of erythrocytes will not hold in this 

 case. 



* Anat. Anzeig., xlv. (1913) pp. 193-215 (1 pi. and 5 figs.), 

 t Anat. Anzeig., xliv. (1913) pp. 262-9 (2 figs.). 

 % Anat. Anzeig., xliv. (1913) pp. 339-22 (8 figs.). 



