176 BULLETIN OF THE 



]\Iunier-Chalmas sp., and C. seguenzai Menegh. That they are conge- 

 neric with Forbes's species and with Rhizocrinus I have not the smallest 

 doubt; and tlie question therefore arises whether Conocriiius D'Orbigny 

 is to take ])recedence over Rhizocrinus Sars. 



On this subject Prof. Zittel remarks, "Nach den Regain der Priori- 

 tiit gebiihrt dem Nanien Conocrinus D'Orb. die Prioritiit, wcnn gloich 

 die Gattungsdiagnose D'Orbigny's unvoUstUndig und theilwise unrich- 

 tig ist." 



The type on which D'Orbigny founded Conocrinus was the Bourgueti- 

 crimis thoreiiti of D'Archiac,.but his definition of it was so incom2:>lete 

 and so incorrect that, even supposing 8ars had not defined Rhizocrinus 

 as elaborately as he did, I should not admit Conocrinus as a valid genus 

 nntil it had been re-defined. Liitken * remarked, in 18G4, that its dis- 

 tinctness from Bourgiieticrimis was still a matter of uncertainty. D'Or- 

 bigny t spoke of it as " Genre voisin des Bonrgueticrimis, mais sans 

 pii'ces basales comme les Eugeniacrinus " ; and again, " C'est un Bour- 

 gueticrinus ayant la tige comprimee, mais avec mie seule serie de pieces 

 basales." If he considered it as near Boiirgudicrinus and as resembling 

 Eugeniacrinus, why did he omit it altogether from the tal)ular scheme 

 of the Apiocrinidoe, which appears on page 2 of his " Ilistoire Naturelle 

 des Crinoides Vivans et Fossiles," and contains the names of both those 

 genera 1 It would seem from his reference to the absence of any tertiary 

 species of Bmirgueticrinus on page 9G that ho included them all in 

 Conocrinus, which would belong to a different family altogqther. This 

 shows how he had misunderstood its real character and affinities, and as 

 a matter of fact his description of it as having no basals is entirely 

 incorrect. They are visible enough in D'Archiac's figures of B. thorenti 

 (the type-species of Conocrinus), and in other closely allied species. 

 Lastly, the remark that Conocrinus is a Bourgueticrinus with a com- 

 pressed stem, is worthless as a generic description, when the latter genus 

 itself is described as having a round or compressed stem. 



The differences between the two types are of an entirely diftcrent char- 

 acter from those mentioned by D'Orbigny, which would be absolutely 

 unintelligible in the absence of figures or of original specimens. I feel it 

 only right, therefore, to ignore Conocrinus altogether, and to adopt Sars's 

 well-known genus Rhizocrinus. 



The differences between Ajyiocrinus and Millericrinus on the one hand, 

 and Bourgueticrinus and Rhizocrinus on the other, have led Mons. de 



* Loc. cit., p. 212. 



t Prodrome de Paleontologie Stratigraphiriue Universelle, 1850, Tom. IL p 832. 



