36 SUMMARY OF CURRENT RESEARCHES RELATING TO 



number of heart-beats increases and a larger amount of blood is sent to 



the head. 



In the first stage the constrictor contracts, the heart-beat is acceler- 

 ated, the veins and sinuses are distended, the eyes protrude. In the 

 second stage the protrusor contracts, along with others which press upon 

 the distended vessels, raising the blood-pressure still more. The dis- 

 tension of vessels and elevation of blood-pressure, aid in exuviation by 

 stretching the skin and by facilitating the processes of metabolism. 

 The moulting mechanism may be set in motion experimentally by 

 applying court plaster to the head. In snakes and turtles the protrusor 

 oculi is wanting. 



Skeletal Sexual Character in Argentine Frog.*— J. Lesage de- 

 scribes the extraordinarily strong and ridged character of the humerus 

 in the male of Lepto dactyl us ocellatus. This is an adaptation to the 

 great muscular development of the forearm, one use of which is in 

 embracing the female — the embrace lasting 15 to 20 days. 



Age and Rate of Growth of Eel.f— K. J. Genzoe has found that 

 the minute, deeply imbedded scales of the eel {Anguilla vulgaris), show 

 annual rings (as in many other fishes), from which the age may be read. 

 These scales appear first on the eels of 18 cm., and the fact that those 

 below this fall into two groups of size points to the conclusion that two 

 years pass before the scales appear. The males stay 4 \ to 8£ (usually 

 5| or 6 J) years in fresh-water; the females stay somewhat longer, for 

 g| to 8£ (usually 7£) years. 



Brain of Lepidosiren.} — G. Elliot Smith finds that the features of 

 the brain in the Dipnoi, considered as a whole, are nearer to those of 

 Amphibians than to those of any other Vertebrata. In the cerebral 

 hemisphere there is a definite pallial formation, or cerebral cortex, 

 distinctly separated from the ependyma as a clearly defined layer of 

 nerve-cells. This pallial formation is homologous with the pallium of 

 Amniota. An outstanding feature is the relatively enormous develop- 

 ment and the high degree of specialisation of the tuberculum olfactorium. 

 Three elements may contribute, to the formation of the choroid plexus 

 of the lateral ventricle in different Vertebrata : (1) The roof of the fore- 

 brain ; (2) a band formed from the attenuation of the pallio-thalamic 

 junction ; and (3) the secondarily thinned caudal part of the para- 

 terminal body. 



Vascular Filaments on Pectoral Fin of Lepidosiren paradoxal — 

 AV. E. Agar found some breeding males with vascular filaments on the 

 pectoral as well as on the pelvic fins. He asks whether it is a homceotic 

 variation, or is it a reminiscence of the former exclusively respiratory 

 function of the fin (on Graham Kerr's theory of the origin of the paired 

 limbs from external gills). The period of the functional activity of the 



* C.R. Soc. Biol. Paris, lxv. (1908) pp. 463-4. 



t Rep. Dan. Eiol. Stat, to Board of Agric, xiv. (1908) 30 pp. (1 fig.). See also 

 Zool. Zentralbl., xv. (1908) p. 713. 



% Anat. Anzeig., xxxiii. (1908) pp. 513-40 (18 figs.). 

 § Tom. cit., pp. 27-30 (5 figs.). 



