508 Chronicles of Science. [July, 



the results of actual experiments made for the prevention of their 

 attacks, or the destruction of the insects themselves. The memoirs 

 must be sent to the Secretary, No. 12, Bedford Eow, London, with 

 mottoes, on or before 31st December, 1865, when they will be re- 

 ferred to a committee to decide upon their merits. The prize 

 memoirs shall be the property of, and will be published by, the 

 Society. 



A statement of the number of insects in the National Collection 

 may not be uninteresting. The entomological department of the 

 British Museum, we learn from the ' Reader,' contains 130 cabinets, 

 3,755 drawers, and 121 store boxes, the number of specimens being 

 not less than 904,605. This wealth of species is unequalled in the 

 museums of Europe ; but it is rendered almost wholly unproductive 

 of benefits to science from the want of able assistance to place it in 

 order, since there is but one assistant employed in the supervision of 

 the entomological department. 



Some observations upon Crustacea have been made by Dr. Fritz 

 Muller, for the purpose of testing the Darwinian hypothesis, on the 

 principle of genealogical classification. Having constructed such a 

 genealogical tree for the Crustacea, he has deduced certain necessary 

 consequences, which if not verified by facts would be a fatal blow to 

 Darwinism ; but which, if they proved true, would furnish a strong pre- 

 sumption in favour of the theory. Hitherto his deductions have been 

 verified. Thus in each family of crabs, we find as exceptions to the 

 normal mode of life, certain terrestrial species. It is permissible to 

 suppose a priori that these must present certain modifications of the 

 respiratory apparatus to enable them to respire air, and that a multitude 

 of arrangements may be capable of leading to this result. If he found 

 in the terrestrial species of different families the same arrangements 

 for affecting aerial respiration, the Darwinian theory would be irre- 

 vocably condemned ; but if he should discover differences so complete 

 as not to be reducible to the same type, this would certainly furnish 

 a strong argument in favour of the theory ; and the latter alternative 

 has proved to be the true one. The three groups of Crustacea — viz. 

 the stalk-eyed, sessile-eyed, and entomostraca — present essentially 

 different modes of development. Darwin's theory, by assigning a 

 common ancestor to all these Crustacea, presupposes that the 

 ancestor itself presented these different modes of development. This 

 hypothesis appears a bold one, and it has been reserved for Dr. 

 Muller to demonstrate its truth, by the discovery of species with a 

 mixed development, presenting the characters of the different groups. 

 The most remarkable of these is a macrourous genus Peneus, which 

 quits its egg, not under the form of a Zoea, but under that of a true 

 Nauplius, perfectly similar to those of the Entomostraca. The 

 integuments of the Nauplius are then cast off and a true Zoea issues 

 from it, and this Zoea-phase afterwards gives place to one which can 

 only be called a .Mf/sis-phase. Finally, a last moult converts this 

 pseudo-Mysis into a true Peneus ; nor is this singular mode of de- 

 velopment an isolated fact. The sessile-eyed Crustacea (Amphipods 

 and Isopods), should, according to the Darwinian theory, have passed 



