1888. ] 233 [Keyes. 
doubt that a sudden death had overtaken them in the midst of their 
repast.’’ 
1844. De Koninck,* though possessing no specimens in which these 
gasteropods were associated witb crinoids and probably having in mind 
living forms, states that in consequence of the habits which the animals 
of this genus (Caupulus) have of attaching themselves to foreign bodies 
and remaining fixed during life, the margins of the shells become adapted 
to all the irregularities of the surface in contact. 
1847. In America the first mention of the association of Platyceras and 
* fossil crinoids was by Yandell and Shumard.} - The specimen they refer 
to was afterwards described by the formeras Acrocrinus shumardi. These 
authors seemed to have adopted the views of the Austins, and remark that 
they believe ‘‘the carnivorous habits of the crinoideans have been clearly 
made out.”’ 
1851. L. P. Yandell,t in a paper On the Distribution of the Crinoidea 
in the Western States, corroborates the statement made four years previous, 
and is ‘‘ satisfied as to the carnivorous habits of the crinoidea.’? At Cin- 
cinnati he noticed several specimens of Glyptocrinus decadactylus Hall 
with gasteropods entangled in the arms. Reference is also made toa 
Platycrinus from Warsaw, Ill., and several specimens of Actinocrinus§ 
with Platycerata attached. 
1855. Yandelll| described and figured Acrocrinus shumardi with a 
Platyceras attached to the vault. It is the same specimen referred to by 
Yandell and Shumard in 1847, and the views there expressed are here 
repeated. 
1862. Richard Owen{ considered that the Platycerata constituted the 
principal food of certain crinoids and therefore gave without description 
the name Platyceras pabulocrinus to a gasteropod ‘found on Platycrinus 
hemisphericus. 
1866. In Meek and Worthen’s discussion** of the genus Platyceras two 
paragraphs are devoted to the consideration of the probable habits of the 
species of this group. An instance is cited in which the calyptreean shell 
is attached to the side of a Pentremites godoni so as to entirely cover one 
of the pseudo-ambulacral fields and two of the intermediate areas, the line 
of contact being such as could not have resulted from accidental pressure. 
The improbability of the earlier views that the crinoids were in the act of 
devouring the gasteropods is here clearly shown. 
1867. H. Trautschold{{ figured and described Capulus parasiticus on 
* Desc. des Anim. Foss. (de Belgique), p. 332, 1842-4. 
+ Contributions Geol. Kentucky, p. 25, 1847. 
t Proc. Am. Asso. Ady. Sci. 1851, p. 234. 
§ Actinocrinus as then used has since been subdivided into a number of genera. 
| Amer. Jour. Sci., (2), Vol. xx, p. 185. 
91. Surv. Indiana, p. 364, 1862. 
*# Geol. Illinois, Vol. iii, p. 384. 
tiEinige Crin. und andere Thierreste des Jiingeren Bergkalks im Gouy. Moskau, p. 41, 
1867. 
