86 JOURNAL OF THE [February, 



are provided with sucking disks, and with bristles armed at their 

 extremities with minute claws ; but the posterior feet have no 

 sucking disks. The mouth has a double upper and lower lip, 

 between which play the jaws armed with teeth, moving over each 

 other like the blades of scissors, and resembling the claws of a 

 lobster.' Centuries ago, Scabies or Itch was ascribed to a para- 

 site, but not until the modern microscope was used in the study 

 of such subjects, could a sight be obtained of the creature itself 

 and its wonderful structure." 



ACHENIA OF CYPERUS FLAVESCENS, L., AND C. DIANDRUS, TORREY. 



Dr. N. L. Britton called attention to the difference in surface 

 markings of the achenia of these two sedges. In C. flavescens 

 the superficial cells on the achenia are oblong, about four times 

 as long as broad. In C. dicuidrus, and in our other native species 

 of the subgenus Pycreus, these are quadrate, and much larger 

 than in C. flavescens, which may thus be distinguished from the 

 others. Mr. C. B. Clarke, in a monograph on the Indian species 

 of Cyperus {/our. Liftn. Soc. (Botany), XXL), has used these fea- 

 tures to advantage in classifying the species. Dr. Britton's in- 

 vestigations confirm Mr. Clarke's diagnosis in this respect. 



FUNGI WHICH CAUSE DECAY IN TIMBER. 



P. H. Dudley : "The fungus Lentinus lepideus, Fr., an Agaric, 

 is the one I have found to be very destructive to railway sleepers, 

 bridge-timbers, and planks, made of yellow, or Georgia pine 

 {Finus palustris, Mill.). It has a whitish, delicate mycelium, its 

 hyph^ being i to 1.5^ in diameter, and when attacking the 

 wood at its ends, is able, in many cases, to separate the annual 

 rings. It^secretes fluids possessing acid reactions, readily 

 softens the thin-walled tracheides, causing their decomposition, 

 and produces an abundance of crystals of the form of oxalate, 

 and sometimes of phosphate, of lime. In some cases, carbonate 

 of lime has also been found. The mycelium once started, se- 

 cretes enough moisture for its own nourishment and develop- 

 ment, and rapidly multiplies. Decomposition of the wood, the 

 so-called 'dry-rot,' — which, contrary to the general opinion, never 

 takes place in the absence of moisture — as rapidly ensues, unless 

 the moisture be dried by external agencies. In railway sleepers, 

 as soon as the thin-walled tracheides are softened by the action 



