94 Scientific Intelligence. 



giving an account of the structure and general character of the 

 order and its literature, and good plates of the different species, 

 give additional value to this admirable monograph. w. g. f. 



3. TIeber Sclerotinia cinerea und Sclerotinia fructigena ; by 

 M. Woronin, Mem. Acad. Imp. Sci. St. Petersburg, viii, Ser. x, 

 No. 5, pp. 38, pi. 6, in part colored, 1900. — In the present sequel 

 to the series of papers on Sclerotiniae by Woronin, the author 

 gives a full account of his studies and experiments in relation to 

 the two species to which is due the rotting of cherries, apples and 

 other fruits of the order Rosaceae. The rotting in this case, 

 however, is not the ordinary moist rot, but what may be called a 

 dry wilting. In neither species was Woronin able to observe the 

 cosporic stage, but he considers that they belong to the genus 

 Sclerotinia since their conidia are those of that genus, although 

 the disjunctor is less clearly marked. By some writers S. cinerea 

 and S. fructigena have been considered forms of one species, but 

 Woronin distinguishes the latter species by its larger conidia, 

 which are yellowish and not gray. He withdraws his previously 

 expressed opinion that the conidia are uninucleate, and states 

 that they are multinucleate. S. cinerea is the species which has 

 caused serious disease of cherries in many places, while S. fructi- 

 gena causes a disease in apples and pears. These diseases are 

 usually manifested in the fruit, but may attack twigs and leaves. 

 Both species may occur on drupaceous as well as pomaceous 

 fruits or may, at least, be made to grow on decoctions of them, 

 but in nature Woronin believes that in all serious epidemics it is 

 S. cinerea which affects cherries and stone fruits, while in the case 

 of apples and other pomaceous fruits the fungus is S, fructigena. 



w. G. F. 



4. On Platydorina, a new Genus of the Family Yblvocidae, 

 from the Plankton of the Illinois River ; by C. A.Kofoid. Bull. 

 Illinois State Lab. Nat. Hist., V, 419-440, pi. 28. Dec. 28, 1899.— 

 In this paper the writer supplements his previous notice of the 

 genus Pleodorina by an account of another very interesting mem- 

 ber of the Volvox family discovered during his investigation of 

 the plankton of the Illinois River. The new genus Platydorina, 

 represented by the single species P. caudata, is one of the most 

 peculiar members of this peculiar family, and is characterized by 

 its horseshoe-shaped coenobium, composed of 16 or 32 cells with 

 three or five prolongations or tails on the posterior end of the 

 coenobium. The cells of the two sides of the compressed and 

 flattened coenobium intercalate so that the flagella are found 

 upon both faces on alternate cells. The different cells are, how- 

 ever, all similar, and the marked polarity of this genus is indi- 

 cated by the general outlines of the coenobium rather than by a 

 difference in the cells as in some other genera, as Pleodorina. 

 Although the sexual reproduction was not seen, the non-sexual 

 reproduction and the cell structure and arrangement are consid- 

 ered by the writer to indicate its near relationship to Eudorina. 

 At the end of the paper is a key to the genera and species of 

 Volvocidae. w. g. f. 



