IOWA ACADEMY OF SCIENCES. 105 



priority ascends beyond Rostafinski, does it therefore at the 

 risk of endless confusion and uncertainty in the great majority of 

 cases. Some years ago the botanists present at the session of 

 the A. A. A. S. , concluded that in describing Phenogams one 

 should not transcend a particular edition of Lincceus; a better 

 rule is that which ascends to the earliest accurate description; no 

 farther. Accordingly for the great majority of slime -mould 

 species I should draw the line at Rostafinski's work, 1875. 



The exceptions are the few which the rule of accurate 

 description would carry behind the Polish publication, where 

 Rostafinski discarded a name simply because for some reason 

 or other Rostafinski did not like it. As an illustration, take 

 the little, not uncommon, species called by Rostafinski — 



Cornuvia circuniscissa (Wallr.) R. 



The synonyms, as quoted by Rostafinski, are: 



Lignidium quercinum Pr. 1825. 



Trichia circumscissa Wallroth. 1833. 



Arcyria glomerata Pr. 1849. 



OpMotheca chrysospei'ma Currey. 1854. 



Trichia curreyi Cronan. 1867. 



The only names accompanied by their authors by descrip- 

 tions at all definitive are the last two. The genus Lignidium, 

 as defined by Link, certainly referred to forms belonging to the 

 Physarece, if to Myomycetes at all, so that that generic name 

 cannot stand, nor can Pries have had our species in mind, since 

 his description refers, probably, to some Physarum. Trichia cir- 

 cumscissa Wallr. undoubtedly comes nearer to it, but our species 

 is not circumscissile, so that it is doubtful whether Wallroth, 

 even, had in view the same species. Currey, who comes next 

 on the list, by judicious description and carelully drawn figures, 

 having, as we think properly, separated from the Trichias the 

 genus OpMotheca, ignored ah preceding specific names, suppos- 

 ing any to have been up to this time affixed, and called the 

 species we ha^ve before us 0. chrysosperma. Rostafinski now 

 recognizes Currej's work, but rejects his generic name on the 

 grounds of inapplicability in primary significance to all the 

 species included. He therefore coins a new generic name — 

 i. e. Cornuvia — and goes back to Wallroth for specific name, a 

 thing that Currey should have done had Wallroth's description 

 been of sufficient exactness to make sure to Currey 's mind, as it 

 seems it did to Rostafinski's, that Wallroth was actually describ- 

 ing the same specific form. The criticism of Rostafinski will, 



