306 SMITHSONIAN INSTITUTION 



Dimerocrinus nobilis (op. cit., pp. 7-8). His error, therefore, was not in the perception of 

 general systematic relations, in which he showed excellent judgment, but in the misunder- 

 standing of the genus Dimerocrinus — a difficulty in which he was not without company, as 

 the synonymy of that genus will demonstrate. 



In 1881 and 1885 Wachsmuth and Springer (Rev. Pal., pt. 2, p. 231 ; pt. 3, p. 144) 

 referred Pacht's species to Taxocrinus, a genus which as then understood would include both 

 this form and the somewhat similar "Taxocrinus" thiemei. In 1886 Wenjukoff 1 described 

 a specimen from Isborsk, northwestern Russia, under Pacht's name, referring it with doubt 

 to Taxocrinus. 



In 1895 Professor Rowley described and figured a beautiful new species of this type 

 from the Devonian of Missouri, for which he proposed a new name, Aristocrinus ; to make 

 assurance doubly sure against possible preoccupation of the name, he proposed as an alter- 

 native Callaway crinus. 2 He evidently did not intend to include Pacht's species in his genus, 

 since he made no reference to it. 



In the meantime Quenstedt (1876, Petref. Deutschland, Bd. 4, Abth. 1, p. 520) discussed 

 the oligoptilus of Pacht at some length, showing that it differed essentially from the English 

 species described under Dimerocrinus; and he pointed out in detail a character of undoubted 

 generic importance, viz., 20 main arms (Hande) bearing ramules (Nebenarmchen) "which 

 stand in only a single row on the inner side of the hands and are so coordinated like the 

 fingers of Pentacrinus that we have here before us a finger-crinoid, Dactylocrinus." He said 

 that these ramules were not pinnules, or they would be biserial and alternating. In his later 

 Handbuch der Palaeontologie, 1885, Quenstedt did not mention the genus; but in 1879 

 Von Zittel (Handb. d. Pal., p. 354) recognized Dactylocrinus with a query, credited it to 

 Quenstedt, and gave a good generic diagnosis in conformity with Quenstedt's observations, 

 referring to the type species as Dimerocrinus oligoptilus of Pacht ; but no further mention 

 of it was made in his subsequent Grundzuge der Palaeontologie. 



The generic type being thus recognized and defined under a valid name, the only ques- 

 tion is to whom it should be credited — Quenstedt or Von Zittel. Quenstedt did not give a 

 formal diagnosis under his name, but his observations contained a clear indication of the 

 characters on which he considered the species to differ from the genus under which it had 

 been described. We have therefore a published name, an intelligible indication of characters, 

 and a well known type species. This brings the case clearly within the twenty-fifth article of 

 the International Code of Nomenclature, and the genus must date from Quenstedt, 1876. 



Rowley described his species originally under Taxocrinus (American Geologist, vol. 12, 

 J 893, P- 3°4) as having twenty stout arms with pinnules. Afterward (ibid., vol. 13, 1894, 

 p. 153) noting the fact that pinnules had not been observed before in any of the Ichthyo- 

 crinidae, he said " if what we have designated arms are really free rays, and the so-called 

 pinnulae arms, we have here an aberrant Onychocrinus or a new generic form." It was this 

 consideration mainly that led him afterward to propose a new genus, and it is evident that 

 the decisive character on which he relied to separate his species from Taxocrinus was that 

 pointed out by Quenstedt as the basis of his Dactylocrinus. If he had seen the figures of 

 D. oligoptilus in Pacht's paper (which is a very rare publication, found in but few libraries 

 in this country) there is no doubt that he would have perceived the relation of the two 

 species. As it is, his independent recognition of the generic importance of the arm structure 

 disclosed by his specimens was a just and valid observation, and I only regret that under the 

 rules of nomenclature the adoption of his name is precluded by the priority of Quenstedt's 

 action. 



1 Faune Dev. Syst. Nordw. u. Cent. Russia, p. 31, pi. I, fig. 11. 

 "American Geologist, vol. 16, pp. 217, 219. 



