•368 PROCEEDINGS OF THE ACADEMY OF [1888. 



It was upon the information derived from these figures that we 

 based our conclusion — hasty as it may have been — that there were 

 two_integuments in these genera, one above the other ; one representing 

 the perisome containing the ambulacra, the other a vault of iri-eg- 

 ular pieces, and to some degree pliable. 



We could not see how two such totally different structures as those 

 shown by PI. XVII, fig. 3a, and PI. VIII, fig. 6, could represent the 

 same elements in one and the same genus, and we therefore adopted 

 the idea of a double covering as the only solution we could find, al- 

 though after considerable hesitation, feeling that such an arrange- 

 ment was quite anomalous, and without a parallel elsewhere. We 

 were also influenced in no small degree by the fact that Prof. Zittel, 

 who had the opportunity to see the Swedish collections, interpreted 

 the structures in a similar way.^ 



We could not, of course, imagine that such magnificent figures as 

 are represented in Angelin's work^ in the absence of any explana- 

 nation to that effect, could be wholly imagiiiary as to the most im- 

 portant parts of the structures illustrated. The fact is, however, as 

 we now know, that all these important figures are to a large extent 

 fictitious ; that the middle portions of them, where the summit plates 

 and covering pieces of the vault shoidd have been found, were not 

 shown in the specimens at all, but were filled in by the artist accord- 

 ing to his own motion of their probable structure. 



The only specimen in the National Museum at Stockholm w^hich 

 shows any part of the vault structure of Crotalocrinus, aside from 

 the original of fig. 3a, PI. XVII, has been sent to us for examination. 

 It is evidently the original from which fig. 7, PI. VIII was composed ; 

 for Dr. Lindstrom informs us that there is no other which can be 

 regarded as the type of that figure. It shows the lanceolate areas 

 and covering plates along the arms beyond the calyx very well, but 



1 Handl). d. Pal. Vol. i, p. 357. 



2 It is but justice to tlie distinguished Swedish paleeontologist to remark tliat 

 his worl.; on tlie Crinoids of Sweden was not complete at the time of his death. 

 His descriptions seem to be rather preliminary notes niaile for his own use, pre- 

 paratory to a more detailed study. These were collected after his death and 

 publislied, together with twenty-nine plates illustrating them, under the direction of 

 the Royal Academy of Sciences of Sweden. It is not strange under such circum- 

 stances there should be errors, and in pointing out some of them in this paper we 

 have no intention of discrediting a work which has been of great service to 

 palaeontology by bringing to notice one of the most magnificent cnnoidal faunae 

 ■ever discovered. 



