INTRODUCTION. 129 



Good illustrations of sponges appeared in the pictorial works 

 of the seventeenth and eighteenth centuries, but they were 

 generally termed pelagic plants or fruits, or were included with 

 corals and bryozoa, under such names as corallioliths, alcyonias, 

 fungites. 



Guettard was the first to publish a more detailed investiga- 

 tion of fossil sponges. His researches were not confined to 

 the description of external features, but made a careful note of 

 the inner construction, the canals and openings. At first 

 Guettard rightly compared the fossil specimens with existing 

 sponges, afterwards he placed them with corals, but ultimately 

 returned to his first idea that they were sponges. His treatises 

 are accompanied by good figures, and undoubtedly rank as the 

 best contributions to the older literature. Parkinson included 

 the fossil sponges with alcyonarians ; he gave careful descrip- 

 tions and very good illustrations of a number of Cretaceous 

 and Jurassic forms, but made no attempt at systematic treat- 

 ment; in his later, smaller work, Parkinson compared some 

 forms with sponges, others with alcyonarians, and Schlotheim 

 took much the same standpoint. 



Fossil corals were figured by Knorr and Walch, and by 

 most of the early writers on palaeontology. Linnaeus gave 

 the Silurian coral fauna of Gothland to one of his students, 

 Fougt, to be described, and Guettard published detailed works 

 on fossil corals from the Dauphine and other parts of France. 

 The fine illustrations of Parkinson represented more especially 

 the coral types of the older strata in England and Scandinavia. 

 Schlotheim also described a large number of species under the 

 vague generic titles of Fungites, Porpites, Hypurites, Madre- 

 porites, Milleporites, and Tubiporites. On the whole, the 

 study of fossil corals was limited to external features; little was 

 known about the organisation of recent corals, and the syste- 

 matic arrangement had no secure basis. 



The knowledge of crinoids had reached a more favourable 

 stage of advancement. The older authors in the sixteenth and 

 seventeenth centuries occasionally figured the stems and crowns 

 of crinoids under the terms of trochite, entrochite, encrinus, 

 pentacrinus, or under such popular terms as fossil "wheels," 

 "lilies," "pennies," etc. The classificatory position of fossil 

 crinoid remains continued, however, quite indefinite until 

 Rosinus in 1718 demonstrated their affinities with existing 

 representatives of the Eiiryalecs^ an Ophiuroid family. Rosinus 



9 



