224 SCIENCE PROGRESS 



calorific quotient of the egg both before and after fertilisation 

 is approximately the same ; the writer therefore concludes that 

 as a " negligible quantity of this energy is expended in bring- 

 ing about the visible morphological structure of the developing 

 ovum, it is probably employed in keeping the living substance 

 itself intact as a physical system." 



Hiroshi Ohshima describes in the Q.J. M.S. (vol. Ixvi, 

 March 1922) cases of situs inversus amongst artificially-reared 

 echinoid larvae. More than 10 per cent, of the larvae reared 

 exhibited this peculiarity, but the young sea-urchins meta- 

 morphosed from such larvae were quite normal externally. 

 In a note on the subject in the same journal. Prof. E. W. 

 MacBride points out that while he brought about the develop- 

 ment of a right hydrocoele in echinoid larvae by stimulation 

 with hypertonic salt solution, Ohshima's results are to be 

 attributed to the checking of the growth of the normal left 

 hydrocoele as the result of starvation. 



The development of the branchial derivatives in turtles 

 is the subject of an investigation by C. E. Johnson, " Branchial 

 Derivatives in Turtles " (jonrn. of Morph., vol. xxxvi, No. 2, 

 March 1922). Three genera were investigated : Chelydra, 

 Chrysemys, and Trionyx. The persistent thymus arises from 

 the dorsal part of the third visceral pouch. A cellular body — a 

 possible rudimentary, transitory thymuS' — arises from the 

 corresponding part of the second visceral pouch. From the 

 fourth pouch, the persisting parathyroid is formed. A rudi- 

 mentary transitory thymus probably arises from the same 

 pouch, but the writer found no definite evidence of a per- 

 sisting thymus arising from this region. Paired ultimo- 

 branchial vesicles are usually present at early stages ; the left 

 one usually grows larger than the other and often attains a 

 considerable size. By the time of hatching, it has been 

 transformed almost completely into a lymphoid organ which 

 is quite distinct from the thyroid. 



Other recent papers are : 



Penners, Andreas, " Die Furchung von Tuhifex rivtilorum Lam.," Zool. 



Jahr., Bd. 43, Heft 3. 

 Patten, B. M., " The Formation of the Cardiac Loop in the Chick," Amer. 



Journ. of AnaL, vol. xxx. No. 3. 

 Herrick, C. J., " Some Factors in the Development of the Amphibian 



Nervous System," Anat. Rec, vol. xxiii, No. 5. 

 Stunkard, H. W., " Primary Neuromeres and Head Segmentation," 



Journ. of Morph., vol. xxxvi. No. 2. 

 Lamont, a., " On the Development of the Feathers of the Duck during the 



Incubation Period," Trans. R. S. Ed., vol. Uii, Part L 

 IsHii, O., " Observations on the Sexual Cycle of the White Rat," Anat. Ree., 



vol. xxiii. No. 5. 

 Allen, E., " The Oestrous Cycle in the Mouse," Amer. Journ. of Anat., 



vol. xxx. No. 3. 



