234 SCIENCE PROGRESS 



The original finding of Martini, therefore, although not abso- 

 lutely true, is still approximately so. 



The living and fixed eggs of Strongylocentrotus were utilised 

 by Painter in " Contributions to the Study of Cell Mechanics, 

 ii. Monaster Eggs, iii. Narcotised Eggs " (Journ. Exp. Zool. 

 vol. xxiv. Jan. 191 8) to examine the changes in the proto- 

 plasm during cell-division. These activities have been noted 

 by other authors who did not investigate their cause. As 

 certain narcotics allow the division of the egg to take place 

 without the formation of asters, these are excluded as causa- 

 tive agents, and it appears as if the nucleus alone is responsible 

 since its activities always precede those of the cell proto- 

 plasm. 



Other papers include : " Cushion Cells of the Pharynx 

 of Prorhynchus applanatus Kennel " by Kepner and Scott 

 (Journ. Morph. vol. xxx. March 191 8) ; " The Eye of Polycystis 

 goettei (Bresslau)," by Kepner and Lawrence (ibid.) ; " The 

 Oogenesis and Early Embryology of Ascaris canis Werner " by 

 Walton (ibid.) ; " Differential Susceptibility and Differential 

 Inhibition in the Development of Polychete Annelids," by 

 Child (ibid.) ; " Studies of Amitosis ; its Physiological Rela- 

 tions in the Adipose Cells of Insects, and its Probable Signifi- 

 cance," by Nakahara. 



Vertebrata. — A fairly extensive study of the functional 

 activities of an Ascidian has been made by Hecht and re- 

 corded by him in " The Physiology of Ascidia atra Lesueur, 

 i. General Physiology, ii. Sensory Physiology " (Journ. 

 Exp. Zool. vol. xxv. 191 8). The movements are brought 

 about by several sets of smooth muscles using the test as an 

 exoskeleton. Food in the form of plankton is caught up by 

 mucous and passed across the branchial wall into the oesophagus. 

 The animal is sensitive to tactile stimuli, but only to light of 

 very high intensity, and the ocelli do not appear to be photo- 

 receptors. It is also sensitive to heat and chemical stimuli. 



Other papers include : " On the Branchial Epithelium of 

 Ammoccetes," by Wallin (Anat. Rec. vol. xiv. March 191 8). 

 The History of the Eye Muscles " has been worked out 

 by Neal (Journ. Morph. vol. xxx. March 191 8), who finds that 

 the first myotome gives rise to the muscles innervated by the 

 oculemotor nerve, the superior oblique is derived from the 

 second myotome, while the external rectus has a double origin. 



