164 NOTES AND MEMORANDA. 



its armature of spines and setaa. The chitin of the limbs and other 

 parts covered by the carapace is very thin, so that the respiratory 

 surface is much increased. It is doubtful whether this is due to the 

 paucity of oxygen in the medium inhabited, or the thickness of the 

 carapace and its consequent unfitness for respiratory purposes, or 

 because of the exertion of burrowing through the mud which these 

 animals have to undergo. The compound eyes are always much 

 reduced, or may even be entirely absent. At the same time the 

 simple eyes are increased in size and importance, being sometimes 

 larger than the compound eyes, and sometimes having the whole 

 visual function assigned to them. 



The remainder of the paper is taken up with a description of the 

 typical genus Uyocryptus, and of its various species, the chief points 

 in the anatomy of which are illustrated in the plate which accom- 

 panies the paper. 



New Cryptogamic Journals. — In addition to ' Brebissonia,' a 

 monthly journal devoted to Algology,* which first appeared in July 

 last year, and the bi-monthly ' Kevue Bryologique,' which has existed 

 for five years, we now have a new journal, published every three weeks, 

 for Fungi — the ' Eevue Mycologique,' edited by M. C. Roumeguere, 

 the first number of which appeared in January last. The contents of 

 this nimiber will be foimd noted in " Bibliography." 



Unit of Micrometry. — We stated at p. 353 of vol. i. that the reso- 

 lution of the Indianapolis Congress, which recommended the y^ of a 

 millimetre as the unit of micrometry, was approved by the New York 

 Microscopical Society. At a subsequent meeting, however, some of 

 the members had the subject reconsidered, and the former approval 

 was unanimously rescinded. The editor of the ' American Journal of 

 Microscopy,' to whose views reference was also made at p. 353, says 

 the action of the Congress " is now generally considered to have 

 been too positive and definite, for the simple reason that the subject 

 had not been sufficiently discussed or considered by the members 

 present." 



The Microscopical Section of the Troy Scientific Association have 

 appointed a committee to confer with other microscopical Societies on 

 the subject of micrometry, and that committee, by a circular issued in 

 December last, suggest the appointment of a larger committee (on 

 which each Society should be represented by a member), whose duty it 

 shall be to investigate the questions mentioned below, confer with 

 the Societies and with persons known to be experts in this depart- 

 ment, and report to the American Society of Microscopists, at their 

 next meeting at Buffalo in August. They state that their Society, 

 whilst earnestly desiring the success in some practicable form of the 

 movement suggested by the Congress, believe that much further pre- 

 paration will be required to enable the American Society to take 

 definite action, and that, to prevent the movement being a failure, it 

 must be entered upon after mature deliberation and full consultation, 

 and in such manner as to secure the general and cordial assent of 

 * Sec thia Journal, vol. i. (1878) p. 368. 



