28 SUMMARY OF CURRENT RESEARCHES RELATING TO 



usually occur in pairs, sometimes in threes. The femoral valve which 

 Grruby described in 1 Mi' occurs in the femoral vein before its anasto- 

 mosis with the external iliac. That which Gruby described at the con- 

 fluence of the three tributaries of the superior vena cava is really a 

 complicated system of sigmoid valves. Valves also occur in the toad. 



Glandular Endothelium of Lymphatic Canals and Renal Capilla- 

 ries in Tadpoles.* — L. Bruntz finds that these elements are true nephro- 

 cytes, comparable cytologically and physiologically to the nephrocytes of 

 Invertebrates, such as the branchial nephrocytes of Crustaceans and the 

 pericardial nephrocytes of Insects. 



Minute Structure of the Internal Ear.f — W. Kolmer has investi- 

 gated this subject in the pig, calf, goat, and horse, and describes the 

 histology of the ductus cochlearis, Corti organ, stria vascularis, Reisner's 

 membrane, and membrana tectoria. In general the structure of the 

 auditory organ corresponds in these larger mammals, both anatomically 

 and histologically, with the descriptions given by other authors for smaller 

 mammals. In all the forms examined, Held's support apparatus of the 

 Corti organ could be demonstrated with essentially the same structure. 

 Stress in particular is laid upon the " Horhaaren " and their relations in 

 the cochlea, macula? and crista?, which according to Piper have to do 

 with hearing: rather than with static orientation. 



i & 



Regeneration of Cross - striped Muscle in Vertebrata4 — A. 

 Schmiucke reviews the literature on this subject and gives an account 

 of his own researches on Ichthyopsida. For example, in Triton tceniatus 

 and T. cristatus regeneration goes on by means of sarcoplasts, which are 

 transformed into long spindle-like elements ; by amitotic nuclear increase 

 syncytial bands arise rich in nuclei and give rise to young muscle fibres. 

 The greater part of the muscle fibres is formed by superposition and 

 confluence of the long spindle elements which have arisen from the sar- 

 coplasts. The mode of nuclear divisions in muscle regeneration is 

 mitotic and in the isolated sarcoplasts amitotic. In fishes regeneration 

 sets in late, in the frog relatively early, in newt, tree-frog and turtle 

 after a longer time. In extent it takes place very slightly in fishes, it 

 goes further in the frog and tree-frog, but only in newts can it be 

 regarded as anything like complete. 



Observations on the Living Developing Nerve-fibre.§ — Ross G. 

 Harrison has been able to watch what takes place in the end of a growing 

 nerve, and finds that the nerve-fibre develops by the outflowing of 

 protoplasm from the central cells. The protoplasm retains its amoeboid 

 activity at its distal end, the result being that it is drawn out into a 

 long thread, which becomes the axis cylinder. No other cells or living 

 structures take part in the process. 



The development of the nerve fibre is thus brought about by means 

 of one of the very primitive properties of living protoplasm, amoeboid 



* Arch. Zool. Exper., vii. (1907) Notes et Revue, No. 4, pp. cxi.-xiv. 

 t Arch. Mikr. Anat., lxx. (1907) pp. 695-767 (4 pis.). 

 % Verh. Phys. Med. Gesell. Wiirzburg, xxxix. (1907) pp. 15-130 (1 pi.). 

 § Amer. Journ. Anat., vii. (1907) pp. 116-18. 



