The name Buthotrephis gracilis Hall 
Epwin W. HUMPHREYS 
While engaged in the work of identifying and naming certain of 
the specimens in the paleobotanical museum of the New York 
Botanical Garden my attention was called to the confusion that 
obtains in connection with the use of the name Buthotrephis 
gracilis Hall; and in the hope of establishing hereafter the correct 
application of this name it has been deemed advisable to present 
the following account of its origin, together with a brief discussion 
of the principles of nomenclature that are involved with it: 
In 1843 Hall* described and figured a fossil fucoid from the 
Clinton group, under the name Fucoides gracilis. 
In 18477 he described and figured a similar fossil from the 
Trenton limestone, under the name Buthotrephis gracilis. 
In 1852+ he described and figured another specimen from the 
Clinton Group under the name Buthotrephis gracilis, and included 
with it, as a synonym, his Fucoides gracilis, followed by the note 
“Not B. gracilis, Pal. N. York, Vol. 1, pag. 62, pl. 21, fig. 1. The 
species of the Clinton group will retain this name by precedence, 
and that of the Trenton limestone may be changed to B. tenuis.” 
From a consideration of the above facts it may be appreciated 
that in common usage the name Buthotrephis gracilis Hall might 
be meant to indicate either one of the two species which Hall 
regarded as distinct from each other and as representing two dis- 
tinct and rather widely separated geologic horizons. A critical 
study of literature relating to the subject has shown this to be the 
case and, further, that the changes in nomenclature suggested by 
Hall have received but scant attention on the part of most writers. 
These conditions have, in consequence, led to more or less confu- 
sion, and to considerable doubt in many instances as to which 
species is meant where a fossil fucoid is referred to as Buthotrephis 
*Nat.. Hist. N. WV. Pt. FV. napa Fourth Geol. Dist. 69, f. 14. 
fIbid., Pt. VI, Paleont. N. Y. 1: 62. pl. 27. f. 1 
fIbid., Pt. VI, Paleont. N. Y. 7. 18. pl. 5. f. ra—rd. 
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