HISTORY OF RESEARCH. 7 



figures two now hydroids. One oi' tlieiu is a Cori/iie, n genus wliich he adopts from a MS. of 

 Gaertnei- ; the otlicr lins no gonoiic name assigned to it by Pallas ; it can, however, be easily 

 recognised as a CIma, a genus founded a few years afterwards by Gmelin for the Hydra 

 squamnfa of Miiller. Pallas's figures, however, though sufficient for idc^ntification, cannot be 

 compared, either in beauty of execution or in truthf'uhiess, to those of Trembley, Jussieu, or 

 Ellis. 



A much better figure of a Chwa was given shortly afterwards by the Danish naturalist and 

 traveller, Forskal, in his ' Icones Rerum Naturalium,'' where the species is named Hydra 

 multicornis ; and in the same work, besides two other tolerable figures of hydroid trophosomes, 

 we find some very expressive and, indeed, up to that time, the only really recognisal)le ones of 

 true hydroid Medusae. 



Among the means which tend most powerfully to advance the progress of the natural history 

 sciences is an accurate and expressive iconography. The beautiful figures of Trembley and of 

 Ellis hold in this respect the first rank. As we have already seen, Jussieu had given an admirable 

 figure of Tabularia indivisa, aiul Forskal some very good ones of other hydroids, while some 

 tolerable figures of a Tabularia and of some Sertularian and Campanularian hydroids had 

 been published by Raster ;" but hitherto no attempt had been made at the publication of 

 coloured drawings. Between 1777 and 1780, however, were issued the first two fasciculi of the 

 ' Zoologia Danica' of O. F. Miiller,^ which after Midler's death was continued with additions by 

 Abildgard. It contains coloured figures of Scandinavian animals, mostly invertebrate, from the 

 surrounding seas, and amongst them several hydroids. la the accuracy, beauty, and abundance 

 of the figures, too much praise cannot be given to the ' Zoologia Danica,' which marks out an era 

 in zoological iconography. 



The posthumous work of Ellis and Solander,' published in 1786, contains many hvmdreds 

 of figures, chiefly of corals, but having also among them several hydroids. Many of the figures 

 contained in this work are masterpieces of iconography. 



Esper also gives us a most lal)orious iconography, partly copied, partly original, consisting of 

 coloured figures of' corals, sponges, &c., as well as of numerous hydroids.^ Where the hydroid 

 figures are not copied from Ellis they are vastly inferior to those of the English naturalist. 



The naturalists who during the eighteenth century contributed most to advance our 

 knowledge of the Hydroida close with the name of Cavolini. Cavolini, like Ellis, studied the 

 Hydroida in a living state. His investigations were made in the Bay of Naples, where he dis- 

 covered many hydroids previously unknown, and determined many points of interest in their 

 .structure and physiology. He was the first to observe a Medusiform gonophore in connection 



' ' Icones Rerum Naturalium quas in Itinera Oriental! tlepingi curavit Pctrns Forskal.' Copen- 

 hagen, 1776. The descriptions are contained in a separate volume, published in 1775. 



^ Jobi Basteri, ' Opuscula Subseciva.' Harlemi, 1762. 

 Otho Fredericus Miiller, ' Zoologise Danicae seu Aniraaliuni Danire et Norvegi<e variorum et 

 minus notorum Icones.' Hafnisc, 1777 — 1780. 



* ' The Natural History of many curious and uncommon Zoophytes collected from various parts of 

 the Globe, by the late John Ellis, F.R.S. Systematically arranged and descril)ed by the late Daniel 

 Solander, M.D., F.R.S.' London, 1786. 



' Die Pflan.senthiere in Abbildungeu uach der Natur mit Farben crleuchten uebst Beschrei- 

 bungen,' von Eugenius Johann Cristoph Esper. Nuremberg, 1791 — 1797. 



