404 The American Geologist. jnne, 1893 
must certainly be admitted that brachlopodlsts have often found it dif- 
ficult, and sometimes impossible, to determine to which of two well 
characterized families certain annectent forms should be definitely 
referred. 
In Europe, however, the retention of family designations is not al- 
ways considered incompatible with the modern philosophical and evolu- 
tional methods of class treatment. They have been preserved with ad- 
vantage; for instance, in Mr. A. Smith Woodward's* masterly systema- 
tic classification of the fossil fishes in the British Museum, and also in 
professor W. A. Herdman'sf exhaustive report on the Tunicata dredged 
by the "Challenger" expedition, associated in this case with evolutional 
data and the presentation of numerous phylums showing the inter-rela- 
tions of genera, somewhat after the same plan as that adopted in the 
"Introduction to the Study of the Paleozoic Genera of Brachiopoda." 
With all due respect to the veteran of the old school and the disciple of 
the new, we venture to submit the impossibility of impressing on the 
mental retina a permanent photograph of the innumerable and fascinat- 
ing phylums which they have provided with such industrious research. 
But we are not all endowed with so much insight, knowledge, and ex- 
perience. 
The most revolutionary feature in the present installment of their re- 
searches on the Articjilata is the extreme subdivision to which the great 
group of Orthoids has been subjected. The genus Orthis is absolutely 
restricted to eight species (instead of two hundred), with 0. callactis of 
Dalman as the type, and his early figures and original descriptions are 
judiciously reproduced for the benefit of American students. The re- 
mainder of the large number of species are placed under various new 
genera and sub-genera, or restored to their former appellations. For in- 
stance. Pander's name, Clttamhonites, is once more applied to species un- 
justly usurped by D'Orbigny's Orthisina, and Plectambonitcs of the same 
Russian paleontologist is restored for the Paleozoic species grouped by 
the French conchologists and those who followed them under the genus 
Leptwnaof authors, not of Dalman. The icptonafogosa of this author is 
taken as the type of his genus, the scope of which is thus much restricted, 
and new generic names are proposed for several of the species indiffer- 
ently described as Strophomcnas or Lepta'nas by various authors. 
Linn^'s sub-genus Bilobites is revived for those abnormal bilobed species 
of Orthis, which, according to Dr. Beecher's investigations, originated 
from a normal form at the adolescent and mature stages of growth in 
both direct and indirect lines of development. In view of the extensive 
breaking up of the orthoids, here proposed, into several genera and sub- 
genera, we are willing to confess that to object to the revival of Bilo- 
bites would be but straining at a gnat and swallowing the camel. We, 
however, admit a preference for those among the proposed new or re- 
*A Catalogue of the Fossil Fishes in the British Museum, Part I., 1889: 
Part II., 1890. 
fReports of the "Challenger" Expedition: Tunicata, vols, vi, xiv, and 
xxvi. 
