680 DE. W. B. CAEPEXTER OX THE STETJCTUEE, PHYSIOLOGY, AXD 



and it seems to have been generally accepted, notwithstanding Ellis's own hesitation, 

 since we shall find it to have been the soui-ce of the extraordinary misconception in 

 reo'ard to the natm-e of the Ckinoidea adopted by one of the most eminent Zoologists of 

 the commencement of the 19 th Century, especially distinguished by his knowledge of 

 Invertebrate Animals. 



The discovery of a recent specimen of a pedunculated Criuoid, which was announced 

 by Guettard' in 1755, did not (as might have been expected) supply the correction of 

 this error; for although he noticed the strong resemblance between this so-called 

 Palmier marin and some of the Starfishes described by Linck, yet being unable to 

 discover a central mouth, he seems to have concluded that this resemblance was falla- 

 cious, and to have believed that nourishment was imbibed by the animal through the 

 numerous minute pores which he affirmed to exist at the extremities of the tentacles 

 and pinnules, — thus likening it to the Zoophytic type, although he refrained from 

 ranking it definitely with that group. In his comparison of it with the fossil Crixoidea 

 he made an extraordinary blunder, which was the reverse of that of Lister ; for whilst 

 the latter mistook their summits for radiating and subdividing roots, Guettard imagiued 

 that the more or less regularly ramifying roots of Ainocrini were in reality their summits. 

 Another specimen of the recent Pentacrinus very shortly afterwards (1761) came under 

 the notice of Ellis % whose description of it is entitled "An account of an Encrinus or 

 Starfish, with a jointed stem, taken on the coast of Barbadoes, which explains to what 

 kind of animal these fossils belong, called Starstones, Asterise, and Astropodea. which 

 have been found in many parts of this kingdom." The specimen examined by him was 

 so imperfect that he did not recognize the place of the mouth ; nor did he in any way 

 more distinctly indicate than in the title just quoted the relationship of this organism 

 to the Starfishes. Not ha\ing the base of the stem, he felt himself unable to affirm 

 whether it moved freely through the sea, or was attached to the bottom like Corals and 

 Sponges ; and it is only by inference that it can be concluded that he was led by the 

 study of this specimen to abandon his previous notion of the relationship of the Cri- 

 >'OiDEA to " cluster polypes." 



It was unfortunate for science that Linkjeus, instead of adopting the more advanced 

 views of some of his predecessors as to the true relations of the Criis oidea, was so misled 

 by the jointed structure of their stems as to rank them among Zoophytes in the genus 

 Isis ; whilst he threw back Antedon among the other Starfish, ranking them all together 

 in his genus Asferias\ And this arrangement was left unaltered in the twelfth edition 

 of his 'Systema Naturpe' pubUshed in 1766, notwithstanding the appearance of the 



' Memoires de I'Academie des Sciences de Paris, 1755, p. 260. 



- PMosophical Transactions, vol. lii. part 1, p. 357. 



^ In tlie tenth edition of tte 'Systema Xaturffi,' Holmkv, 1758, which is the fii-st in which species are 

 characterized, we find Comatida named Asterias mdiata, Viudi thus strangely described :—" radiis duplicatis, 

 superioribus pinnatis, inferioribus filiformibus."' It was long before the difference between the true rays and 

 the filiform cin-hi came to be understood. 



