REPORT ON THE CRINOIDEA. 247 
stem- and arm-joints from the Italian Tertiaries, while he revived d’Orbigny’s name 
Conocrinus for d’Archiac’s Bourgueticrinus thorenti, after an interval of nearly twenty- 
five years. During this period, so far as I am aware, no palzontologist had taken any 
notice of @Orbigny’s attempt to differentiate Conocrinus from Bourgueticrinus. The 
first description" which he gave of the former genus (1847 2) ran as follows: “C’est un 
Bourgueticrinus ayant la tige comprimée, mais avec une seule série de pieces brachiales, 
sans pieces basales;” and he referred to it one unnamed species from the Suessonien 
(Lower Eocene). Three years later (1850) he spoke of Conocrinus as “genre voisin des 
Bourgueticrinus, mais sans pieces basales, comme les Hugeniacrinus;” and he mentioned 
Bourgueticrinus thorenti of dArchiac as belonging to this generic type.’ Meneghini has 
shown, however, that two species were described under this name by dArchiac. One 
is a much elongated type, first described in 1846, and probably that referred to by 
@VOrbigny 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 the Hugeniacrinus 
pyriforms of Minster. This species was not referred by d’Orbigny to his new genus 
Conocrinus, though undoubtedly belonging to it, as pointed out by Meneghini. But it 
was retained by him in Hugeniacrinus, so that the only species of Conocrinus recognised 
by @’Orbigny was the elongated Bourgueticrinus thorenti of @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 position of the sutural lines, 
while they are certainly placed wrongly in his figure,’ according to 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 so characteristic 
of Bourgueticrinus ; while the presence of basals below the radials or “ piéces supérieures ” 
of Bourgueticrinus thorenti was distinctly described by d’Archiac, though he probably 
figured them incorrectly. Nevertheless, Conocrinus is a Bourgueticrinus without basals, 
and d’Archiac’s species in which basals are present is made the type of the genus ! 
Neither does it help in the differentiation of the two genera to speak of Conocrinus as 
a Bourgueticrinus with a compressed stem, when the stem of Bourgueticrinus itself is 
described 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 Hugeniacrinus in the absence of basals, why was it omitted in his scheme 
of classification of the Apiocrinidee, published in 1858, from the fourth section comprising 
Eugenacrinus alone,’ and distinguished by having only “une série de piéces au sommet” ? 
On p. 95 he pointed out that no Tertiary species of Bourgueticrinus were then known, 
from which one may infer that the Tertiary fossils previously referred to this genus 
" Cours elémént. de Paléontol. et de Géol. stratigr., t. ii., 1852, p. 147. 
* Prodrome de Paléontologie stratigraphique universelle des Animaux Mollusques et Rayonnées, t. ii. p. 322. 
% Mém. Soc. géol. de France, ser. 2, t. ii. p. 200, pl. v. fig. 20. 
' Cours élément, de Paléontol. et de Géol. stratigr., t. ii., 1852, p. 147. ® Hist. Nat. des Crinoides, p. 2. 
