IN THE MORPHOLOGY Oi' THE CYSTIDEA. 3 



Zalil Secbs bestimmt und belierrscht, eine Zahl,'welche sich auf keine Weise mit 

 Fiinf vereinigen lasst. Der Kelchboden bestebt aus vier ungleicb grossen 

 Asseln, welche, wie vorber gezeigt worclen ist, sich obue Miilie zu secbs ganz 

 gleieben und abnlicben Asseba zerlegen lassen. Secbs Seitenassebi, secbs 

 Scbulterblatter, bilden den Kelcb, und secbs Arrne erbeben sicb auf seinem 

 Eande, drei doppelte namlicb und drei emfacbe. Das alles ist den iibrigen 

 Crinoideen ganz fremd." 



Hall *, in 1852, referred to the four basals, six costals, six 

 scapulars, and two interscapular plates of Caryocrinus ; while 

 Eoemer t described the cup as dicyclic, with four basals, six para- 

 basals, six radials, and two interradials, or, as we should now say, 

 four infrabasals and six basals. It is therefore not a little sur- 

 prising that Grottsche should have endeavoured to reduce the 

 syrametry of Caryocrinus to that of a pentamerous type like 

 Actinocrinus, from which Yon Buch had so carefully distin- 

 guished it. 



Few recent writers, however, seem to have understood that 

 the cup of Caryocrinus is hexamerous with a dicyclic base, fol- 

 lowed by radials, though both facts are clearly explained by 

 Quenstedt %. Zittel §, for example, calls the four unequal plates 

 which rest upon the stem the basals ; but his nomenclature goes 

 no further, though his account of the number of plates in the 

 dorsal cup is correct enough. Steinmannj| also says that"Zum 

 basalen Kranz gehoren 4 Flatten," which are follow^ed by a 

 second row of six, alternating with the plates of the first 

 and third cycles. But then he goes on to say "Der dritte 

 Kranz setzt sich ebenfalls aus 6, etwas niedrigeren Tafeln 

 zusammen." He here omits all notice of the two plates which 

 are intercalated within the ring of radials, each resting on the 

 truncated end of a large anterolateral basal (PI. I. fig. 2 ; 13, 18). 

 The appendages of the adjacent radials encroach more or less upon 

 these plates, which were called interscapulars by Hall, and may 

 perhaps now be considered as true interradials, corresponding to 

 the similarly situated plates in Thamnatocriniis and Slioclocrinus' 



These eighteen jjlates of Caryocrinus reappear, plate for plate, 

 in Von Koenen's two genera, Corylocrinus and Juglandocrinus, 



* ' Palieontology of New York,' vol. ii. 1852, p. 216. 



t 'LetbEea Geognostica,' Ed. i. Tbeil 2, 1852-54, p. 269. 



X ' Petrefactenkunde Deutscblauds,' Bd. iv. 1876, 1874-76, p. 662. 



§ 'Handbucb der Palteontologie,' Bd. i. 1876-80, p. 418. 



II ' Elemente der Palaontologie,' 1888, p. 183. 



