^y^ SCIENCE PROGRESS 



The cytoplasmic structures in the egg of Echinarachnius 

 parma are described by H. Hibbard in the Jr. of Morphology, 

 vol. xxxvi, No. 3 (" Cytoplasmic Inclusions in the Egg of 

 Echinarachnius parma"). Fat droplets are present in the un- 

 fertilised egg, but they disappear during early cleavage stages. 

 The writer suggests that the small spherical mitochondria, 

 which occur scattered throughout the cytoplasm, are formed 

 from fat droplets. Nutritive bodies, containing a fatty com- 

 ponent, are also described, and these are believed to be associated 

 in their origin with the mitochondria. 



It was found that there was no morphological difference in 

 the cytoplasmic contents of the egg, when fertilised with 

 sperms of the same, or of a different species (Arbacia). 



The Septem^ber number of the Q.J. M.S. contains a short 

 paper on " Further Observations on Chromosomes and Sex- 

 determination in Abraxas grossulariata " by the late Prof. 

 L. Doncaster, which is edited by Ruth C. Bamber. As the 

 result of staining sections of the eggs of Abraxas during 

 maturation divisions, with various dyes, it is suggested that 

 " there is a certain amount of chromatin left behind, on the 

 equator of the spindle, by the chromosomes when they move 

 apart at anaphase. If this be true, ' it is at least conceivable 

 that the sex-chromosomes, in the eggs of all-female broods, 

 eliminates so much that it becomes functionless as regards sex- 

 determination,' and that here may lie the explanation of the 

 production of all-female families from eggs, some of which con- 

 tain twenty-seven and others twenty-eight chromosomes." 



J. Turchini, in a paper entitled " Etude histologique de la 

 poche du noir des Cephalopodes dibranchiaux " {Archives 

 d'Anat. Micr., Tome xviii, Fasc. 4), describes the histology of 

 the ink-sac, and also the cytological processes involved in the 

 secretion and excretion of the ink. Mitochondria play the 

 fundamentally important part in the formation of the melanin 

 of the ink, while the mucus is elaborated by the ground 

 cytoplasm of the cells of the glandular epithelium. 



In the same journal L. M. Betances describes " Les cellules 

 du sang de quelques Lamellibranches." The physiological role 

 of these cells is comparable to that of the blood cells of other 

 animals. However, they have not equivalent chemiotactic 

 power for certain chemical reagents. Phagocytosis is limited 

 to certain cells {les cellules hemohistoblastiques). 



In a paper on " A Critical Study of the Facts of Artificial 

 Fertilisation and Normal Fertilisation {Q.J. M.S., Sept. 1922), 

 J. Gray puts forward evidence in favour of the view that 

 " the activation of an unfertilised ^gg by a spermatozoon is 

 due to the electro-motive force set up when the two gametes 

 come into contact. The inert egg is activated by the sperma- 



