244 SMITHSONIAN INSTITUTION 



genus. Therefore Forbesiocrinus is without a type species — its type belonging to a prior 

 genus ; it becomes a synonym of that genus and must be abandoned. Or — 



2. True, the authors believed their type species to be the same as Phillips's species, listed 

 it as such in the synonomy, and noted its occurrence as from both English and Belgian locali- 

 ties. In this they were mistaken. But they described their species under the name Forbesio- 

 crinus nobilis, from original material, with good figures, and also gave a clear generic 

 description and diagram founded wholly upon their own specimens and not in any wise upon 

 the characters of the English species, which although erroneously identified by them, is in 

 fact totally different. Hence the error of the authors was not in their definition, but in their 

 synonymy ; and notwithstanding De Koninck and Le Hon's statement the type species is 

 not, and never could have been, Taxocrinus nobilis Phillips, but is Forbesiocrinus nobilis 

 De Koninck and Le Hon ; — a name attached to a definite form, with adequate description 

 and figures. Thus we have a genus duly published, with a diagnosis, a generic diagram, and 

 a described and figured species under it ; therefore the name is valid, and stands for the type 

 and species which the authors actually figured and described, regardless of what they called 

 it in their synonymy. 



In these circumstances to hold the name invalid, so as to warrant the proposal of a new 

 one in place of it, would in my opinion be invoking a very narrow and doubtful technicality 

 for an unnecessary and insufficient purpose ; whereas to maintain the name will not only 

 leave the credit where it belongs and avoid much needless confusion, but will be consistent 

 with the spirit of the International Code, and in my opinion in no wise countervailed by its 

 letter. This was the view I adopted in 1902, and further consideration has shown me no 

 reason to change it. 



The earliest known occurrence of this genus, as before stated, is in the Mountain lime- 

 stone of Belgium, and in the approximately equivalent Waverly — Choteau — Knobstone of 

 the United States. The F. wortheni type begins in the upper division of the Burlington 

 limestone; and although crinoids in the lower division are very abundant, finely preserved 

 and of great variety, not a specimen belonging to this type has been found from it among 

 all the great collections made at the typical locality during the past 50 years. This type 

 reached its culmination in the Keokuk limestone, both in abundance and variety, and ended 

 in the Warsaw ; it is found in fine preservation at many localities in Iowa, Illinois, Missouri, 

 Indiana, Kentucky, and Tennessee. The specimens in the Warsaw are usually large, and of 

 striking appearance. Some of the species described are exceedingly well marked, while 

 others are poorly defined, and some undoubtedly synonyms. The genus has never been 

 recognized in either the St. Louis or Kaskaskia, although in the literature several species of 

 it will be found recorded from those formations. It is one of the most conspicuous forms 

 of all the Carboniferous Flexibilia, being rivaled only by Onychocrinus of the Taxocrinidae. 



The specimen described by McChesney as Forbesiocrinus pratteni is not from the Car- 

 boniferous of Alabama as stated in the description, but from the Helderbergian of western 

 Tennessee, and is a Camerate crinoid, Scyphocrinus. 



The types represented by F. nobilis and the later species like F. wortheni fall into two 

 rather sharply differentiated sections, which might upon some grounds be placed in different 

 genera. But as in other strong Carboniferous genera, like Taxocrinus and Onychocrinus, it 

 has been found best to admit a wide range of variation in the interbrachial structures rather 

 than to subdivide them upon too fine distinctions, I think it preferable to do so in this 

 case, especially as we thus avoid changing the generic name of a large number of species, 

 including those by which the genus is best known. 



The number of described species remaining under this genus is rather large ; some are 

 clearly synonyms, and in many of those retained the characters are not easy to define, being 

 mainly founded upon slight variations in form and proportions which shade into one 

 another. Ten species are recognized, which may be arranged as follows : 



