ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
623 
conditions. It is not a direct expression of variation in tlie quantity 
of some particular kind of energised matter. Variations in the internal 
conditions produce an apparent increase, diminution, or subdivision of 
the growth force, because those conditions determine the possibilities 
for a longer or shorter or different sequence of chemical changes that 
express themselves to us in change of form. In treating of the de- 
generation and death of IAmulus embryos, Prof. Patten urges that the 
structure and function of the organism is a resultant of (1) production ; 
(2) specialisation; (3) longevity; (4) death-rate of cells. The death 
of Limulus embryos is due to a greater reduction in numbers and in 
specialisation of the constituent cells, till only very few and very simple 
cells remain. These also finally disappear. There is no necessity for 
assuming that there is an essential difference between body and germ- 
cells. “ Mortality ” is not necessarily inherent in any living organism. 
It is rather the result of an imperfect organism in which growth, repair, 
and waste continually produce new conditions unfavourable to the con- 
tinuation of the same, to which the organism cannot adapt itself. 
To this somewhat complex and difficult paper Prof. Patten has 
prefixed an analysis which the student will find of considerable assis- 
tance. 
e. Crustacea. 
Indian Crabs.* — Dr. A. Alcock in the second part of his memoir, 
entitled ‘ Materials for a Carcinological Fauna of India,’ deals with the 
Brachyura oxystoma. He adopts as his classification of this tribe, the 
groups originally established by De Haan, that is to say, in opposition 
to some writers, he recognises the Raninidae as true oxystomes. He 
points out that some of the deep-sea forms give the clearest evidence of 
the close relation of the Banina type to the Dorippe type, and afford 
quite sufficient justification for accepting De Haan’s scheme of the oxy- 
stomes almost without modification. 
Thirty-two genera of oxystomes are known to inhabit the Indian 
Seas. Two of these, Heteronucia and Pariphiculus , are new. The 
author gives diagnoses of the tribes of these animals, with keys to the 
genera and to the species. The species are fully described and their 
synonymy is given in detail. Of course, it is difficult for one who is not 
a specialist to judge, but it strikes us that Dr. Alcock has been a little 
too generous in describing new species. 
Habits and Respiratory Mechanism of Corystes Cassivelaunus.f — 
Mr. W. Garstang deals, in the first of his contributions to marine 
bionomics, with the habits of this Masked Crab, as it is popularly 
called. Common all round the coasts of the British Isles in deep water, 
and often in many of the sandy pools on the seashore, its position, as 
systematic studies show, has been much discussed. This Mr. Garstang 
thinks is partly due to the fact that the structure of these animals is 
remarkably modified in relation to sand-burrowing habits. Some of 
the adaptive modifications seen in this crab reappear in others, and have 
led to the supposition that there is a relationship between the two. The 
case, Mr. Garstang remarks, affords a new illustration of the inadequacy 
* Journ. Asiatic Soc. Bengal, Ixv. (1896) pp. 134-216 (3 pis.). 
t Journ. Marine Biol. Assoc., iv. (1896) pp. 223-32. 
