ZOOLOGY AND BOTANY, MIOBOSOOPY, ETO. 407 



they are provided witli powerful locomotor organs; they or their 

 germs may become attached to powei'ful swimmers, wood, or the feet 

 of swimming birds ; and, lastly, they are aided by the wind, for when 

 floating on the water they offer a broad surface. 



The author then proceeds to discuss the results of recent ob- 

 servations which confirm the idea just enunciated ; as examples of 

 geologically old forms we may take the Protozoa, and especially the 

 Foraminifera, several of which have been found by Brady to be 

 cosmopolitan in their distribution ; the Cetacea and perhaps some 

 Cephalopods are good examples of strongly swimming forms ; the 

 cosmopolitanism of many pelagic Crustacea and the localization of 

 Coelenterata is explained by the resistent chitinous shell of the one 

 and the delicacy of the tissues of the other set of forms ; at the same 

 time, some ccelenterate species are very widely distributed. 



Influence of High Pressures on Animal Tissues.* — M. P. 

 Eegnard has investigated the increase of weight in organs and 

 tissues subjected to high pressures (100-400 atmospheres), and he 

 finds a great increase in the quantity of water in the tissues ; it is 

 not yet certain whether this is due to water directly entering, or 

 whether it combines with the albuminoids, and, after the removal of 

 the pressure, escapes and infiltrates the tissues. 



B. INVERTEBRATA. 



Mollusca. 



Formation of Chromatophores in Cephalopoda.t — In working 

 out the development of the chromatophores in Sepiola Bondeletii 

 M. C. Phisalix comes to the same conclusion as Blanchard, Girod, and 

 others, that the fibres radiating from the cell are not muscular but 

 connective tissue. In the centre of a mass of yellowish pigment a 

 large rounded vesicle appears, with the nucleus at the periphery of 

 the protoplasm, as in a fat-cell; in this cavity refringent coloured 

 granules collect. The cells surrounding this vesicle equatorially are 

 arranged in a radial fashion ; their nuclei elongate, and their proto- 

 plasm becomes converted into fibrils, while their central ends become 

 continuous with the protoplasm of the central cell. The nucleus of 

 this latter soon loses its structure, but retains its size and shape ; the 

 large vacuole of the cell is surrounded by a ring of smaller vacuoles, 

 and the coloured granules in this vacuole move about ; this has given 

 rise to the idea that the chromatophores may be amoeboid. 



Embryology of Patella.| — Dr. W. Patten communicates a most 

 interesting investigation on the embryology of Patella. 



1. Preparation of the embryos. — The opaque, blueish-green ova 

 were rendered partly transparent by a preparation of acetic acid and 

 glycerin. For studying the more complicated internal changes, 

 sections were made of embryos killed in acetic acid, preserved in 

 alcohol, and stained with alcoholic borax-carmine or Kleinenberg's 

 haematoxylin. 



* Comptes Eendus, cii. (1886) pp. 173-6. t Ibid., pp. 775-7. 



X Arbeit. Zool. Inst. Univ. Wien, vi. (1886) pp. 1-26 (5 pis.). 



