TUNIOATA. 297 



and structure of the new species, and even in some cases to give additional figures of 

 species that are known to science. 



In regard to the classification, I have arranged the species under their Families, 

 and have not made use of any higher groupings. There is still some difference 

 of opinion amongst authorities as to the correct position and divisions of that 

 polyphyletic group, the compound Ascidians, and until these matters are settled 

 there can be no practical inconvenience in omitting, in a report of this nature, the 

 names of larger groups and in making use merely of the " Family" designations. 



Sluiter, in 1900, remarked upon the scarcity of Ascidiiche in the Pacific Ocean, 

 and stated that the "Schauinsland" collection of 36 species contained no representative 

 of that family. Since then, however, he has described a large number of new species 

 of Ascidia from Malaysian seas in his ' " Siboga " Report.' I was also struck, when in 

 Ceylon, by the paucity of Ascidiidae, especially when compared with northern and 

 southern seas, where, in places, they constitute the characteristic feature of the 

 Ascidian fauna. Another family most feebly represented in the tropics is the 

 BotrylKdae, which contains, perhaps, the most abundant of colonial forms in northern 

 temperate seas. The most notable character of the Ceylon Ascidian fauna is the wide 

 distribution and abundance of the genus Leptoclinum, and, in fact, of calcareous and 

 sandy forms in general. Species of Leptoclinum, and to a less degree of Psamma- 

 plidium, are found nearly everywhere around Ceylon, and are the largest and most 

 conspicuous, as well as the most abundant of compound Ascidians. Species of 

 Rhabdocynthia with calcareous spicules are also abundant, and some of them have a 

 sandy covering. Sandy simple Ascidians are very numerous, and belong to at least 

 three distinct families. Although most of them at first sight might be supposed to 

 be Molgulidae, the majority are Cynthiidse, and some are Ascidiidee. Sandy balls of 

 very similar appearance have proved to belong to the genera Ascidia, Styela, Poly- 

 cur pn, Rhabdocynthia, Microcosmus, Molgula and Ctenicella. As is usual in warmer 

 seas, the majority of the simple Ascidians are species of Polycarpa and Styela, but 

 Rhabdocynthia, Ecteinascidia and the Polystyelidse may also be mentioned as 

 characteristic forms. 



Sltjiter, in his ' " Siboga " Pteport,' estimates that there are about 200 species of 

 Tunicata in the Malaysian seas, and nearly the same number (183 recorded in 1899) 

 are known from the coasts of Australia. Compared with these figures, the 64 species 

 described below seem to represent rather a poor fauna, but even if this be the case in 

 regard to species, it is certainly not true of individuals. Both on the coral reefs of 

 Galle and Aripu, and also on some of the paars in the Gulf of Manaar. compound 

 Ascidians are abundant, and in some places fine specimens of Leptoclinum bulk large 

 in the dredge and the collecting jars. 



About three-fourths of the species found seem to be new to science, but that is to 

 be expected on a coast where the Ascidian fauna has not before been specially 

 investigated. 



