14 THE CEINOIDEA CAMERATA OF NOETH AMEEICA. 



priate, as not a single Encriniis or Pentacnmis resembled in the smallest 

 degree a lily, either in stem, root, flower, or bud. Nor did he think it 

 absolutely proved that they were annuals instead of coraline sensitive 

 plants. 



In 1825, Say "^ described three new species under the genus Pentremites, 

 which he made the type of a new family of the Crinoidea, and proposed for 

 it the name Blastoidea. He also described the genus Cari/ocrinites^ which he 

 took to be intermediate between Cyathocrinus and Adinocrinus. In the same 

 year two additional species of Pentremites were described by G. B. Sowerby. 



In the years following up to 1840, a number of new species of Crinoids 

 were described by Mantell (1822), Pander (1830), Steininger (1831, 1837, 

 and 1838), Goldfuss (1832 and 1838), Zenker (1833), Philliios (1835-1836), 

 F. A. Roemer (1836 and 1839), Heisinger (1837), Sedgwick and Murchison 

 (1837), D'Orbigny (1837), Mlinster (1838-1846), and others; but they added 

 little to the general knowledge of the Crinoids. 



L. Agassiz, in his Prodrome d'une Monographic des Radiaires ou Echino- 

 dermes,t referred the Crinoids to the " order " Stellerides, together with the 

 " genera " Comatiila and Mctrsupites, which, as he stated, differ from the 

 Crinoids only in not having a stem. 



J. V. Thompson, in 1836, discovered % that the small species, which he 

 had described in 1827 as Pentacrinim europoeiis, loses its stem at a more 

 advanced stage of growth, and changes into a free-floating Comatula. 

 Thompson also discovered the ovaries along the pinnules. 



Other important discoveries in relation to the anatomy and development 

 of recent Crinoids were made by Adams, Heusinger, Savigny, Delle Chiaje, 

 Blainville, and Dujardin. D'Orbigny in 1839 described the remarkable 

 recent genus Holopus,% a Crinoid not attached by a jointed stem, but by the 

 lower end of the calyx. 



In 1840 appeared the classical w^ork of Johannes Mliller, " Ueber den 

 Bau des Pentacrinus caput-medusa3," || which marked a new era in the history 

 of the Crinoidea, and threw a flood of light upon the whole group. Mliller 

 in this w^ork discussed the relation between the Pentacrinites and Comatulse, 

 and pointed out the anatomical differences in the structure of Crinoids and 



* Journ. Acad. Nat. Sci. Pliila., Vol. IV., pp. 292-296. 



f Meraoires de la Societe des Sciences Naturelles de Neufchate], 1835, Tom. T, p. 168. 



X Memoir on tlie Starfisli of tlie genus Comahda (Edinburgh New Pliilos. Jouru.. Vol. 20, p. 295. 



§ Wiegmann's Arcliiv fiir Naturgescliiclite, I, p. 185, Taf. 5, Figs. 2-7. 



11 Read before the Berlin Akademie der Wisseuschaften, April 30, 1840. 



