342 SUMMARY OF CURRENT RESEARCHES RELATIXG TO 



same general type and size, but there is no absolute regularity. It is 

 sometimes possible to distinguisb an inner core either non-colourable 

 or faintly colourable, and an outer shell of colourable or chromophile 

 matter. The latter part of individual mitochrondria often fuses to 

 form threads or rods, which then lie in the apparently liquid chromo- 

 phobe part. 



The chondrioplasts of different genera, and often of different species, 

 tend to differ a little in shape and size. The centrosome sorts them 

 out into two equal groups at the prophase of division. Their behaviour 

 is described. The micromitochondria are distinguished from the macro- 

 mitochondria. The changes of the mitochondria in the staining affinity 

 and resistance to fixatives are discussed. Strong evidence is _ being 

 collected against the view that the mitochondria take any part in the 

 transmission of hereditary factors. J- A. T. 



Notes on Thecosomatous Pteropods. — Giuseppe Colosi {Monitore 

 Zool, Ital, 1918, 29, 79-87, G figs.). Attention is 'called to the 

 tetragonal symmetry of the armature of the gizzard in Thecosomata 

 and its marked resemblance to that in Runcinidse. A description is 

 given of the reproductive organs of Cavolinia longirostris ( = Hijalsea 

 longirostris Lesueur), where again there is resemblance to a type like 

 Runcina, the author's general view being that within the Tectibranchs 

 there should be established a section Runcinidea, from which there 

 have diverged the littoral Runcinidse and the pelagic Thecosomata 

 (Cavoliniidse, Limacinidse and Cymbuliidge). J. A. T. 



Structure of Amphibola crenata.— Winifred C. Farnie (Trans. 

 Nnv Zealand Inst., 1919, 51, 69-85, 7 figs.). This is a pulmonale 

 gastropod living on mud-flats on the coast of New Zealand. The gill 

 has been replaced by a lung, but the animal, which is very sluggish, can 

 live immersed in fresh water for a fortnight, in the sea for a month. 

 The minute eye, not previously located with accuracy, is at the tip of 



'e^^? 





O 09 



* l%e 



The end of a tentacle, with the eye, cleared and mounted entire. 

 c, carbonate ; g., lime; l, lens; ^., pigment; ^.,tip of tentacle. 

 Much enlarged. 



the tentacles. An account is given of alimentary, nervous, vascular, 

 excretory, and reproductive systems. Embedded in the connective 

 tissue and amongst the muscles in all parts of the body are numerous 

 bodies composed of carbonate of lime. They are extremely abundant, 

 especially on the mantle-edge. They vary in size, the smallest ones 



