66 NATURAL SCIENCE. July. 



that the subterranean species are more abundantly supplied with 

 sense-organs (other than eyes) than allied surface animals. He is 

 unable to add any fresh information as to the food and food-supply of 

 these Crustacea. With regard to arrested development previously 

 noticed among these animals, Mr. Chilton says he has a good example 

 in Cruvegens fontanns, which has the seventh segment of the peraeon 

 small and without appendages, as is the case in the young forms of 

 many Isopods. Of the habits oi Crungens, he notes that " they ran 

 backward and forward with equal rapidity, and did not seem particular 

 which way they went ; they did not swim, and if they dropped off a 

 plant wriggled helplessly till they reached the bottom." They ran 

 against objects in a way which seemed to indicate that they were 

 totally blind, and he occasionally saw two approach very near each 

 other, apparently without being aware of it, and then suddenly jump 

 apart when they touched. 



Speaking of the age of the cave fauna of New Zealand in parti- 

 cular, the author notes that all the places where subterranean forms 

 are found are marked on Professor Haast's map as either " post- 

 Pliocene alluvium " or " recent alluvium " and mostly in the latter, 

 and he suggests that it is quite possible, if thorough search were to be 

 made, that some species of the genera (especially of Phveatoictis) would 

 still be found inhabiting fresh-water streams among the Southern Alps 

 of the country. The paper is well illustrated by some quarto plates, 

 and is a valuable contribution to a most interesting subject. 



A Criticism and a Theory. 



Gestaltung und Vererbung. Eine Entwickelungsmechanik der Organismen. 

 By Dr. Wilhelm Haacke. Pp. 337, twenty-six illustrations in the text. Leipzig: 

 T. O. Weigel Nachfolger, 1893. Price 8 marks. 



Although Dr. Haacke does not proceed to the display of his own 

 theory until he has spent over one hundred pages in criticising the 

 theories of others, and specially the theory of Weismann, it may be 

 more convenient to attempt at once to give an account of this new 

 panacea for all biological difficulties. His theory is epigenetic in the 

 strictest sense. He believes that the plasma of the whole body of 

 each animal and the plasma of the germ-cells are of the same kind. 

 Hence he thinks that the shape and symmetry of the adult must be 

 explained by the shape and symmetry of the elements in the plasma 

 of the germ-cell from which the adult grew. The plasma is made up 

 of ultimate elements, which Dr. Haacke terms '■^ gemmcE.''' These are 

 rhombic prisms, and the process of assimilation consists of the 

 formation of new gemma. The unformed food of the plasma is built 

 up into the peculiar gemma' of the particular animal, or plant, in 

 some such fashion as inorganic particles grow into crystals under 

 the stimulus of the presence of crystals of their own order. 

 Gemmcv, by the adhesion of their faces, are built up into units 

 of a higher order, called gcmmaria. As out of one set of similar bricks 

 many different castles, depending on the number and arrangement of 

 the bricks in each castle, might be formed, so out of a comparatively 

 small variety of gemmce an indefinite number of gemmaria might be 

 obtained. It is these gemmavia that are the real morphological units. 

 Out of one geimnavium you could tell the whole animal. But as from 

 their size, if from no other reason, the investigator is exceedingly 

 unlikely ever to see the gemmariiim, Dr. Haacke goes to work the 

 other way about, and endeavours to deduce, from the shape of adult 

 organisms, the shape of their gemmaria. This he does in a sufficiently 



