canses ,c:re;it dama^iic to plaiilalioiis ol' JA/Vx halsann-a iii llic ('ii\ii-(iiis 

 of (;iiol[)li in Ontario. Tlionoii it n.av he \vv\ prohaMc that tlie 

 Tnugus mentioned does not Ixdunu' to tlie uenns Tflinni(iloslivin((, vel 

 it appears from Doiikktv's artiele that it ureallv inipe<les llie ui-owlli 

 of the trees l>v ehoosinu' theii- ikhmHcs as snhstrate. Ahont llie checkinu: 

 of the evil nothiii,u- is mentioned hv Doni-'.KTV, so that we eaimol 

 piDJit hv adxiee fi'om Ontario. Xo snflei'inLi' Irees weix' found al 

 Xnnspeet except at "de Oroute Ihnite ". 



EXOSPOKINA Ori). n. ^. 



Funui expositi vel en(U\i>eni, stromate nnllo vel parnni evolnio, 

 Cüiiidiis in catenas stipalas digeylis, 8in«;nlatini seeedenlihus, humo- 

 niür[)his, eonlinnis, eoloratis. 



E. Larieis Ori). — Slroniatihns aniplii<ienis, expositis, imneti- 

 formihns, nigris, catena;? coiiidiornm longinscnlas, in placentam con- 

 vexani arcte condensatas, gereiitihns; conidiis primo angnlatis, deni(|ne 

 glohiüujsis, conlinnit;, 5 — (> X -^ /'' ^iiVU'datim .secedcntil»ns, ferrngineis. 



EXPLANATIOxN OF THE PLATE. 



Fig. A. Needle of Larlx decidua ; magnification 10 times; with the hlaek spots 

 of Exosporina Laricis Oud. 



Fig. B. Hypliac or libhons, extending over llie leal' and in various places grown 

 out to small-celled little disks, fi'om which latci' the cunidia, connected to strings, 



•II • AT -ÖÖ 



Will arise magn, 



"" 1 



Fig. C. Ripe cushion of strings of conidia, as they would appear on a cross- 



•jOt) 

 section. Masn, — . 

 1 



Fig. D. Part of such a cushion, enlarged . Each separate string shows a 



spherical top-cell. 



Fig. E. Gorda's picture of Trimmatostroma Salicis. 

 Fig. F. Sagcahdo's pictme of Exosporiion fniciicola. 



1 am mncli iinh^hled to Mr. C J. KoMN(r at Hnssnin, who has 

 been kind enough to draw the })late for me. 



Mathematics. — "PiXckkr's numhcrs of a cm-re in >SV '>v Prof. 



P. n. SCHOITK. 



The Pi/ücIvIsk's numhers of a cui-nc in the space S„ with ii dimen- 

 sions have heen gi\'en foi' the lirsl time hv \kk()NKsk {Mufli. AhikiIi'ii, 

 \'oi. ii), page 1115). yei tliev have heen seldom ap|»lied alliiough dating 

 from 1<S(S2. This is pi-ohahlv diu' to the mort' or less awkwai'd 



