284 THE NORTH AMERICAN SLIME-MOULDS 



itself sufficient, — because of their minuteness, and consequent apparent 

 paucity. They may be common, but none the less seldom seen. The 

 comatrichas afford an illustration. There are several very small 

 species. C. pulchella, C. laxa, C. ellisii may be mentioned. C. pul- 

 chella has been studied nearly a hundred years and has a synonymy 

 accordingly. In 1875 Rostafinski in the material, and among the 

 descriptions, thought he recognized two distinct forms, and went on to 

 give them names; the first in honor of Persoon, C. persoonii, should 

 show an ovate or ovate-cylindric outline with acuminate tip; the sec- 

 ond should be truncate and represent a type first described by Berk- 

 eley under a name given by Babington, C. pulchella. Berkeley's draw- 

 ing shows a sporangium with tip acuminate ! Lilac or violaceous tints 

 attracted attention in the spores of C. persoonii only; in C. pulchella 

 all is ferruginous. Curtis is especially commended for noticing the 

 fact in describing S. tenerrima, here included as we see. 



Comatricha gracilis Wing, is slender, cylindric and has small spores 

 hardly reaching 6 /x; should perhaps be now set out as a separate 

 species; it is evidently purely an American phase. 



Our figures, Plate XII., 16 and \6a, 18 and 18 «, show C. pul- 

 chella and C. gracilis, respectively, extremes. Plate XIII., 4, shows 

 an ovate form not very unusual. This and C. gracilis occur on living 

 leaves. 



C. ellisii is another of this minor series, very constant in its delicate 

 beauty, but approaches C. nigra rather than the others here discussed. 



C. laxa, as the name implies, shows an open construction, suggested, 

 perhaps, by Rostafinski's photographic print, but better brought out 

 by Celakowsky, Alyx. Bohm., Tab. 2, Figs. 7 and 8. 



e. It has been shown ^ that the process of cell-division in the spore- 

 plasm of the myxomycete is not dissimilar to that obtaining under the 

 same conditions in higher plants. On this supposition we have expla- 

 nation of spore-division in Ceratiomyxa and can understand the 

 adherence of spores now and again notable. Once the latter phe- 

 nomenon was thought peculiar to the genus Badhamia; but the un- 



1 Farr. Cell-di'vision in Pol. Mother-cells, Cobcea scandens, Bull. Tor. Bat. 

 CI., Vol. 47, pp. 325-38. 



