382 SCIENCE PROGRESS 



In describing the mode of locomotion of these same Polyclads 

 in a second paper, " The Role of the Nervous S3^stem in the 

 Locomotion of Certain Marine Polyclads," Olmsted points out 

 that locomotion is essentially the same in these organisms as 

 in the Molluscs. This is, therefore, another instance of evolu- 

 tion along the same lines in two quite different groups. 



A further paper dealing with experimental work on Plana- 

 rians, " Regeneration und Transplantation, ii Teil," appears 

 in the Archiv fur Entwick. der Organ., July 1922. 



Vertebrate Morphology. — In a paper " On the Endocranial 

 Anatomy of some Oligocene and Pleistocene Mammals " [Jr. of 

 Comp. Neur.y vol. xxxiv. No. 4, Aug. 1922), R. L. Moodie 

 has described a number of endocranial casts of mammals from 

 the White River Beds of South Dakota which range from 

 Lower to Middle Oligocene, and two brain cases from the 

 Pleistocene deposits of the Ranchola Brea of Southern California. 

 From the types studied the writer concludes that there has 

 been no cerebral development in the rodents since Oligocene 

 times, while the Insectivora, as indicated by Ictops, have 

 retrograded in cerebral structure. Both the aeluroid and 

 cynoid carnivores studied indicated clear cases of cerebral 

 evolution since Oligocene times. 



Other papers of special interest are the following : 



Dawson, A. B., " The Cloaca and Cloacal Glands of the Male Necturus," 



Jr. of Morph., vol. xxxvi, No. 3, June 1922. 

 Hay, O. p., " On the Phylogeny of the Shell of the Testudinata and the 



Relationships of Dermochelys," Jr. of Morph., vol. xxxvi, No. 3, June 



1922. 

 Krieg, H., " Streifung und Stromung," Archiv fiir Entwick. der Organ., 



July 1922. 



General Experimental Zoology. — A great deal of work has 

 been done in this country and abroad on the transplantable 

 tumours of mice, so that special interest attaches to a paper 

 on " A Genetic Analysis of the Factors underlying Susceptibility 

 to Transplantable Tumours," by L. C. Strong {Jr. of Expt. 

 Zool.y vol. xxxvi, No. i, July 1922), in which is described 

 the result of transplanting tumours into genetically homogeneous 

 races of mice. The tumours used in this research were two 

 adenocarcinomata of the mammary gland, which had arisen 

 spontaneously. In general, no rh3''thms of tumour growth were 

 found to take place, but sudden fluctuations in growth activity 

 might sporadically occur, which it is suggested might be due 

 to a process analogous to mutation. 



Race was found to be the primary factor which determined 

 whether or not a given individual did or did not grow the 

 tumour progressively. " Susceptibility and non-susceptibility 

 are manifestations of the genetic constitution of the individual." 



