•S' 



REPORT ON THE CRINOIDEA. 247 



stem- and arm-joluts from the Italian Tertiaries, while he revived d'Orbigny's name 

 Conocrinus for d'Archiae's Bourgueticnnns thorenti, after an interval of nearly twenty- 

 five years. During this period, so far as I am aware, no palaeontologist had taken any 

 notice of d'Orbigny's attempt to differentiate Conocrinus from Bourgueticrinus. The 

 first description' which he gave of the former genus (1847 Vj ran as follows: " C'est un 

 Boiirgueticrinus ayant la tige comprimee, mais avec une seule serie de pieces brachiales, 

 sans pieces basales ; " and he referred to it one unnamed species from the Suessonien 

 (Lower Eocene). Throe years later (1850) he spoke of Conocrinus as "genre voisin des 

 Bourgueticrinus, mais sans pieces basales, eomme les Engeniacnnns;" and he mentioned 

 Bourgueticrinus thorenti of d'Archiac as belonging to this generic ty|ie.- jMeneghini has 

 sho-mi, however, that two species were described under this name by d'Archiac. One 

 is a much elongated type, first described in 1846, and probably that referred to by 

 d'Orbigny in the following year; while the other that was not noticed till 1850, the year 

 in which the second (first ?) description of Conocrinus appeared, is tlie Eugeniacrimn 

 pyriformis of Miinster. This species was not referred l)y d'Orbigny to his new genus 

 Conocrinus, though undoubtedly belonging to it, as pointed out by Meneghini. But it 

 was retained by him in Eugeniacrinus, so that the only species of Conocrinus recognised 

 by d'Orl:)igny was the elongated Bourgueticrinus thorenti of d'Archiac. The figures and 

 descriptions of this type given by the latter author are somewhat incomplete. He had 

 very few specimens, and was exceedingly doubtful about the jiositioia of th(^ sutural lines, 

 while they are certainly placed wrongly in his figure," according io which the second 

 radials rest upon the sutures of the first. There is likewise no indication of an enlarge- 

 ment of the uppermost stem-joints so as to form a "summit," which is sd characteristic 

 of Bourgueticrinus ; while the presence of basals below the radials or " pieces superieures " 

 of Bourgueticrinus thorenti was distinctly described by d'Archiac, though he probably 

 figured them incorrectly. Nevertheless, Conocrinus is a Bourgueticrinus without basals, 

 and d'Archiae's species in which basals are present is made the type of the genus ! 



Neither does it help in the difterentiation of the two genera to speak of Conocrinus as 

 a Bourgueticrinvs with a compressed stem, when the stem of Bourgueticrinus itself is 

 descriljed as being compressed.'* I find very considerable difficulty in comprehending 

 what d'Orbigny really meant by Conocrinus. If it be "voisin de Bourgueticrinus," but 

 also resembles Eugeniacrinus in the absence of basals, why was it omitted in his scheme 

 of classification of the Apiocrinida^, published in 1858, from the fourth section comprising 

 Eugenicicrinus alone,^ and distinguished l^y having only " une serie de pieces au sommet"? 

 On p. 95 he pointed out that no Tertiary species of Bourgueticrinus were then known, 

 from which one may inft>r that the Tertiary fossils previously referred to this genus 



' Conrs elcmt-nt. de PnU'ontol. pt tie Gool. stratif;!'., t. ii., 1852, p. 147. 



2 Prodrome de Paleoutologie stratigraphiqne universelle des Aiiimaux ilollusques et Raj'onnues, t. ii. p. 322. 



^ Mem. Soc. gM. de France, .ser. 2, t. ii. p. 2(»0, pi. v. lig. 20. 



' Conrs (?l('mciit. de Paleontol. et de llenl, stratigr., t. ii., 18.j2, p. 117. '• Hist. Nat. des Crinoides, p. 2. 



