228 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



FEET IN A TRILOBITE. 



Much interest was excited some time ago by the announce- 

 ment on the part of Mr. E. Billings, of Montreal, of the dis- 

 covery of a specimen of trilobite which, in his opinion, exhib- 

 ited unmistakably the possession of legs, and thus solved 

 what was considered an interesting problem in the economy 

 of that animal. Professor Dana, however, assisted by Pro- 

 fessor Vcrrill, has made a critical examination of the original 

 specimen of Mr. Billings, and both came decidedly to the con- 

 clusion that these organs are not legs, but the arches in the 

 membrane of the ventral surface, to which the fqliaceous ap- 

 pendages of the abdomen were attached. Professor Dana 

 calls attention to the fact that similar arches exist in the un- 

 der surface of the abdomen of the macrourous crustaceans, 

 to which the abdominal appendages are articulated. From 

 a careful examination of the subject, Professor Dana con- 

 cludes that, with the exception of these arches, the under 

 surface of the belly of the trilobite must have been delicately 

 membranous, like that of the abdomen of the lobster and 

 other long-tailed crabs. 



NEW FOSSIL CRUSTACEANS. 



According to Mr. Woodward, twenty-three new species of 

 fossil crustaceans have been discovered and described within 

 the last year, one of them, of a very extensive distribution, 

 occurring in LTpper Silesia, in Turin, and in three distinct lo- 

 calities of England. lie gives in his adhesion to the views 

 of Mr. Billings in regard to the possession of feet by trilo- 

 bites, and thinks that this fact, if established, would carry 

 the isopod class back in time to the earliest palaeozoic rocks. 

 He dissents from the views of Dr. Packard, who, from the ex- 

 amination of their embryos, proposes to bring the king-crab, 

 or common horseshoe-crab of the United States, near to the 

 trilobites. 15 A, August 12, 210. 



CLEANING DIATOMS. 



An improved method of cleaning and bleaching diatoma- 

 ceaB is stated by Dr. Maddox to consist in dissolving forty 

 grains of crushed chlorate of potassa in water, with the addi- 

 tion of one and a half drams of hydrochloric acid, the whole 



