ICHTHYOCRINIDAE 265 



were first recognized as the basis of a large division by Wachsmuth and Springer. It was 

 established by Conrad * in 1842, and the type species, /. laevis, described. His diagnosis, if 

 such it might be called, was as follows : " Column round, smooth ; canal small and round ; 

 scapulae with the margins of the articulations parallel, and somewhat imbricated." 



This gave but little insight into the essential characters of the genus, but the accom- 

 panying figure of /. laevis left no doubt as to what was intended to be described. This form, 

 although then first designated as a distinct genus, was not new to paleontology. It had been 

 observed at an early day as one of a few distinct and leading types of fossil crinoids in 

 England, which afterward became the representatives of as many well-marked genera and 

 families. It is rather curious that one of the earliest published figures of the complete crown 

 of a paleozoic crinoid should be that of a fine specimen of this extremely rare genus. John 

 Ellis - in 1762 gave an " Account of an Encrinus, or Starfish, with a jointed stem, taken on 

 the coast of Barbadoes, which explains to what kind of Animal those fossils belong called 

 Starstones, Asteriae, and Astropodia, which have been found in many parts of this King- 

 dom " ; and in connection with a finely engraved drawing of a recent West Indian pen- 

 tacrinite he figured for comparison " two curious fossils " found at Pyrton-passage in 

 Gloucestershire. One of these (pi. 13, Fig. B), showing "all the ramified arms of the head 

 closed up together," is a very characteristic Ichthyocrinus, perhaps /. pyriformis, probably 

 enlarged in drawing. 



Ellis's figure was copied and the type discussed by Parkinson 3 in 1808, as the Glouces- 

 tershire pentacrinite, to which he gave the name of the " Fig Pentacrinite " (p. 274). He 

 also (op. cit., pp. 194-6, PI. XV, fig. 9) figured and described another specimen belonging to 

 some genus of the Ichthyocrinidae from Derbyshire, as the Derbyshire encrinite, which he 

 called the " Cap Encrinite," said to be derived from the great limestone formation of the 

 north of England since known as the Mountain limestone. Parts of this, as Parkinson 

 stated, are filled with amazing quantities of crinoidal bodies and other marine remains, and 

 he evidently considered all the crinoidal remains as belonging to a single form peculiar to 

 that region, as he figured and discussed several unrelated fragments under the same name. 

 The crown as figured (PI. XV, fig. 9) represents an Ichthyocrinoid with broadly rounded 

 base, no interradials, and the arm divisions unequal. In the text the author states that this 

 form is "characterized by its rounded and pyriform figure." At another place (p. 271), 

 when discussing the Gloucestershire pentacrinite, he speaks of the arm division in that form 

 as " closely resembling the divisions that take place in the arms of the Cap encrinite, a first 

 division taking place at about the third articulation, and the fingers which are thus formed 

 being repeatedly subdivided in a dichotomous manner." Parkinson was much impressed 

 with the distinctness of the type, and wanted to call it the " pyriform encrinite," but was 

 embarrassed by the fact that there was another one otherwise widely different which was also 

 pear-shaped (Apiocrinus) ; so he called the latter the' " Pear Encrinite," while to a third 

 equally pronounced type (Eucalyptocrinns) he gave the name " Turban Encrinite " ; and as 

 before stated called the Derbyshire form the " Cap Encrinite." In view of the doubt as to 

 some of the essential structures I have been unable to locate this last form generically. Taking 

 the figure strictly as it appears, it would not fall under any known genus. With a more 

 dichotomous arm-branching it would come nearest to Metichthyocrimis, which has not 

 otherwise been observed in British rocks. And if we also assume some interbrachial struc- 

 tures not shown in the figure, it might belong to Euryocrinus, a form which is typically from 

 the same Mountain limestone area in Yorkshire. Considering the author's emphasis upon 

 the pyriform shape, and the uncertainty about the arm branching, there is a suggestion of 

 Ichthyocrinus; which involves the possibility of the specimen being from the Silurian of the 



1 Jour. Acad. Nat. Sci. Philadelphia, vol. 8, p. 278. 



2 Philos. Trans. Roy. Soc. London, vol. 52, p. 357, pi. 13. 



3 Organic Remains of a Former World, vol. 2, pp. 258, 270, 271, PI. XIX, fig 



