INTRODUCTION. 



PREVIOUS to the publication of the Reports upon the scientific 

 results of the "Challenger" Expedition, comparatively little 

 was known as to the Tunicata of the Australian seas. Some 

 few species had been named and partly described by Savigny, 

 Quoy and Gaimard, Stinipson, J. D. Macdonald, and Heller; 

 but few of these were sufficiently characterised and figured to 

 be really " known " to science. 



Savigny (1816) described Si<jiU.in austral is in considerable 

 detail. Quoy and Gaimard (1834) gave a very insufficient 

 account of various Tunicata which had been found in 

 Australian seas by the French exploring expedition in 

 "IT Astrolabe." Stiinpson (1855) named and very briefly 

 described half a dozen species of Simple Ascidians from 

 Port Jackson. Heller (1878) figured and described, with 

 but little anatomical detail, about twelve species of Australian 

 Simple Ascidians from some of the museums of Europe. 



But our most interesting contributions are due to Dr. 

 J. D. Macdonald (1859) who, while serving as surgeon on 

 board one of H.M.'s ships in Australian seas, found and 

 described the remarkable forms Chondrostackiis sp., Perophom 

 Hutchisoni, Diplosoma Raijncri, Caesira parasitica, C. ficus, and 

 C. pellucula, the last three being species of Molfjula. Some 

 of these older species are, however, so imperfectly charac- 

 terised that it is difficult to recognise them or define them 

 in our modern system of classification. 



The naturalists of the "Challenger" Expedition collected 

 about '28 species of Simple Ascidians and 14 species of 

 Compound in the Australian seas, nearly all of them new to 

 science. 



