cxlviii GENERAL SUMMARY OF SCIENTIFIC AND 



expedition, while stopping in Australia. It seems that the 

 young possess tracheae, which open out by a large number 

 of pores in the side of the body, so that it belongs among the 

 Tracheata, or insects. It differs radically again from them 

 by having the two main nervous cords widely separated, so 

 that, though it has been proved not to be a worm, it remains 

 almost as much of a puzzle as ever. Moseley shows that it 

 has affinities to the true six-footed insects and myriopods, or 

 thousand legs. He also enters into. some speculations as to 

 their ancestry. 



An addition of much value to our knowledge of the mode 

 of growth of Crustacea is afforded by a Russian embryologist, 

 Dr. Bobretzky. He figures the early stages of the pill-bug, 

 or Oniscus murarius, of Europe. 



The mode of moulting of the lobster is for the first time 

 described in the American Naturalist. It is thought after 

 attaining its full size only to moult once a year, at some pe- 

 riod between May and November. On November 8th one was 

 observed to cast its skin. It drew its body out of a rent in 

 the carapace, or shell covering the front division of the body. 

 The shell splits from its hind edge as far as the base of the 

 rostrum or beak, where it is too solid to separate. The body 

 is drawn out of the anterior part of the carapace. It has 

 been a question how the creature could draw its big claw 

 out through the small basal joints. The claw soft, fleshy, 

 and very watery is drawn out through the basal joint with- 

 out any split in the old crust. In moulting, the stomach, 

 with the cartilaginous masses and bands, is cast off with the 

 old integument. The length of the animal observed before 

 moulting was six and a half inches ; immediately after, seven 

 and a quarter an increase of three quarters of an inch. 



Mr. S. J. Smith finds in the tube-building Amphipods cer- 

 tain glands, not before known to exist, which secrete the ce- 

 ment by means of which the tubes or homes of these animals 

 are built. 



An extended and beautifully illustrated memoir, by Weis- 

 mann, on the structure of Leptoclora hyalina, a little Euro- 

 pean Entomostracan, or water-flea, has just appeared. A 

 translation of a summary of his previously published essay 

 on the metamorphosis of the flies has been published in the 

 A merican Naturalist. 



