1898] PENTACBINUS : A NAME AND ITS HISTORY 253 



means that in Waklheim's opinion the l*ahnier marin was the livinoj 

 representative of the genus. He emphasised tliis, because confusion 

 had arisen, thanks to Ellis, Mylius (1753), and otliers, between 

 true crinoids and a polyp dredged off the coast of Greenland — tlie 

 Isis encrinus of Linnaeus (1758), Fennatvia cncrinus, Pallas (1766), 

 or Umbellularia groenlandica, Lamarck (1801). Waldheim, in short, 

 was far from proposing any distinction between the Lias fossil and 

 the living Palmier marin ; on the contrary he was one of the first to 

 refer the latter to the old-established genus. 



For an appreciation of the distinction between our types B and 

 C, couched in scientific language and expressed by a correct nomen- 

 clature, we must turn to H. von Meyer (1837). This eminent 

 palaeontologist described a new crinoid from the Calcaire corallien of 

 Besan9on (Doubs), and, while recognising its affinity to Pentacrinus 

 pointed out the following differences : the cirri are round, not com- 

 pressed rhomboid or oval ; there is no downward prolongation of the 

 radials over the stem ; the arms fork regularly and equally instead of 

 bearing armlets (figs. V., VI.). The last feature suggested the name 

 Isocrinus, the name of the species being /. pendtihcs. It is clear 

 from his description and figures that Von Meyer was dealing with a 

 species of our type C ; this was recognised by P. H. Carpenter 

 (1880,-84). Unfortunately Von Meyer was unable to see the 

 sutures between basals and radials in his specimen, and described 

 it as having a base formed of a single pentagonal plate, with no 

 elements corresponding to what we now term radials. This led 

 either to the non- recognition of Isocrinus, or to its recognition in a 

 wrong sense, as by D'Orbigny (1849), Desor (1845), and Pictet 

 (1857). De Loriol (1889), however, has re-examined the type- 

 specimen of /. peiululus, now in the Natural History Museum of 

 Vienna, and has shown that it possesses five small basals, and five 

 radials. When Von Meyer described the specimen it retained a 

 portion of the stem and cirri, and this no doubt obscured the sutures 

 of the minute cup. Since then these structures, along with portions 

 of the radials and basals, have been destroyed, and the true com- 

 position of the cup exposed. Any doubt that may have existed as 

 to the systematic position of Isocrinus pe7idulus is now dispelled. It 

 is congeneric with all species of our type C, and to them the name 

 Isocririus must be extended. 



In consequence of the confusion caused by the lumping action 

 of Miller, by the erroneous repartition due to the Austins, by Von 

 Meyer's mistake, and by the slow acquisition of knowledge concerning 

 the structure of the cup in Pentacrininae, various other names were 

 proposed subsequently. Cainocrinus, Forbes (1852), of which 

 Picteticrinus,'De Loriol (1875) is admitted by its own author (1897) 

 to be a synonym, was founded on the presence of a closed basal circlet 



