188 SUMMARY OF CURRENT RESEARCHES RELATING TO 



external and internal plates enclosing the fish's temporal fossa, corre- 

 sponding to part of the temporal fossa in mammals. The cerebral portion 

 of the squamosal in man and the zygomatic process are derived from the 

 sphenotic of fishes or that bone fused to the pterotic. The auricular 

 portion of the squamosal corresponds to the cheek-plate of fishes. The 

 tympanic of mammals and the quadrato-jugal of amphibians and reptiles 

 correspond to the pre-operculum of fishes. The jugal corresponds to a 

 fusion of some sub-orbital bones in fishes, and the post-orbitals of fishes 

 fuse with the maxilla to form the maxilla of mammals. There are 

 apparently four distinctly different temporal arches in Vertebrates : one 

 formed by the dermosphenotic and post-orbital (man, npper arch in 

 Hatteria and Crocodile) ; one formed by the cheek-plate of fishes and 

 the post-orbital or jugal (Lacerta, Scleroporus, part of lower arch of 

 Hatteria) ; one formed by the quadrato-jugal and jugal (lower arch of 

 Crocodile, part of lower arch of Hatteria); and one formed by the 

 quadrato-jugal and maxilla (Amphibians). J. A. T. 



Reputed Endocrine Function of Thymus Gland.— Matsuziro 

 Takenouchi {Journ. Exper. Zool, 1919, 29, 311-42, 2 charts). Experi- 

 ments with thymus substance of the albino rat, mainly by means of serum 

 obtained from rabbits immunized with the thymus substance, yield very 

 negative results. " So long as we are unable to maintain a more solid 

 foundation, we cannot accept the specific action of the antithymus serum, 

 nor, furthermore, can we believe [in] any endocrine function whatever 

 of the thymus gland, no matter whether the cortical or medullary portion 

 play the principal role in the physiological function of this gland." 



J. A. T. 



Locomotion in a Spiral. — A. A. Schaeffer {Proc. Amer. Soc. Zooh 

 in Anat. Record, 1920, 17, 342). So far as the author's observation 

 goes, all motile plants and animals, when not guided by orienting senses, 

 are influenced, when freely moving, by some agency so that the resulting 

 path resembles some form of spiral. The great diversity of form 

 exhibited by organisms that move in spiral paths indicates that the 

 automatic mechanism regulating the direction of the path is not depen- 

 dent upon or connected with structure, but is much more fundamental 

 in its nature, affecting the protoplasm directly. J. A. T. 



Cerebral Function in Learning. — K. S. Lashley {PsychohioJogy, 

 1920, 2, 55-128, 4 pis.). There is complete vicarious functioning of all 

 parts of the rat's cerebrum in learning. This seems to hold true both 

 for the cortex and for the underlying structures making up the archi- 

 pallium. Learning may go on with equal speed in the presence or 

 absence of particular specialized areas. There is strong evidence against 

 there being special cerebral areas that have a directive influence over 

 learning, whether it be by " attention," mediated through the frontal 

 lobes, or by the "conscious action " of the brain as a whole. On the 

 contrary, Lashley's results suggest that the only essential condition for 

 learning is the simultaneous activity of two reaction systems which are 



