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BOTANICAL GAZETTE 



genus as to be undesirable. Its nearest affinity may be considered to be 

 Pleodorina californica, originally described by the writer^ and more 

 completely described by Chatton. 5 I now propose to treat this " second 

 form" as the type of a new genus, dedicated under the name Besseyo- 

 sphaera, to the memory of the late Professor Charles E. Bessey. 



This new genus is distinguished from Pleodorina chiefly by having 

 the gonidia scattered among the vegetative cells, instead of being 

 developed from all the cells of the reproductive area. It differs from 

 typical Volvox in having no protoplasmic connections between the cells, 

 and in the lateness of the first visible differentiation of the gonidia, 

 which does not appear until after birth. A study, now in progress, of 

 several species of Volvox collected in the Philippine Islands leads us to 

 anticipate that species lacking the intercellular protoplasmic connections 

 may be properly removed from Volvox, some ranking below and some 

 above Volvox in the scale of development. One or more of these may 

 prove to belong properly in the same genus with the subject of these 

 notes. For the present, however, it is convenient to treat our new 

 genus as monotypic. Taking as a basis the facts stated by Powers, 6 

 and making assumptions which seem to be warranted by the use of the 

 name Volvox for this organism, the following diagnosis is offered. 



Besseyosphaera, gen. nov.— Body a hollow spherical "coenobium" 

 of greenish biciliate cells which lie in the periphery of a gelatinous matrix 

 surrounded by a common hyaline envelope. Gonidia developed from 

 cells distributed among the vegetative cells. No intercellular proto- 

 plasmic filaments. Daughters born before differentiation of gonidia. 

 Sexual reproduction not known. 



B.Powersi, sp. nov— Second for m of Volvox, J. H. Powers, Trans. 

 Amer. Mic. Soc. 27:140-144. pi. 14. figs. 19-24. 1907.— Number of 

 cells in the body about 1000 ("often below," "seldom much above"). 

 Maximum diameter of body about 2000 fx (1800-2500 ^ recorded). 

 Vegetative cells about 12 fi in diameter; separated by 50-200 f*. Go- 

 nidia 10 or more to 78 or more; distributed in two-thirds or four-fifths 

 of the surface of the body; differentiated in the daughters after birth. 

 Daughters less than 150 fi in diameter at birth. Sexual reproduction 

 not known. Habitat not stated (presumably a fresh water pond in 

 Nebraska, United States).— Walter R. Shaw, University of the Philip- 

 pines, Manila, P.I. 



283. i894 W ' W ' R " Pk0d ° nna ' a new genus ° f the VoKouneat - BoT - GAZ " 19 



* Chatton, E., Pleodorina californica k Banyul-surmer: son cycle evolutive et 

 -a -mnmralion phylu^MK'tiqur. Hull. Sri. Franco et Belg. 44:309-331. 19"- 



