FAUNISTIC RESULTS. 445 



living with the Aspidosiphon in the basal cavities of Solitary Corals, are described by 

 Bourxe under the new genus Jousseaumia (Report XXXVIL). The profusion of 

 young Octopods, of undetermined species, on the pearl banks in the Gulf of Manaar 

 was a notable feature during our exploration. Some of the same forms occur at the 

 Maldives. 



The Tunicata are not numerous (66 species), although some of the commoner 

 forms are so abundant that the group bulks large in the general fauna ; 44 species 

 are new to science, and nearly all the species (about 60) are new records for the 

 Ceylon fauna. Calcareous and sandy genera, such as Leptoclinum, Iihabdocynthia, 

 and Psammaplidium, are especially abundant and large. Ecteinascidia, Rhodosoma, 

 Hypurgon, and the Polystyelida3 are other noteworthy forms. As is usual in tropical 

 seas, the Cynthiidse and Styelidse are especially abundant, and the Ascidiidse and 

 Botryllidse are few and of small size. Very few Molgulidte were found, but several 

 other kinds of Simple Ascidians belonging to other families have sandy coverings so 

 as to look superficially like species of Molgula. Pyrosoma, though no doubt some- 

 times present, was not seen ; and the Thaliacea were not especially abundant. The 

 commonest genera are Polycarpa amongst the Simple Ascidians and Leptoclinum in 

 the Compound forms. Although most of the species are peculiar to Ceylon or the 

 Indian Ocean, there are allied forms elsewhere, and it may be said that the fauna 

 shows affinity with that of the Malay Archipelago and that of the Australian seas. 



Seven species of Cephalochorda were obtained, four of which are new to the 

 Ceylon fauna. The collection of Fishes has added considerably to the Ceylon list, 

 but does not call for any special remarks. Adding Thurston's list to our own, the 

 total number of fishes recorded from the Gulf of Manaar is over 226, but I do not 

 doubt that even that could be largely added to by further work. The Maldive list is 

 57 named species, but of these only 17 extend to Ceylon. Thus the percentage of 

 Ceylon tishes recorded from the Maldives is small. The Pleuronectidse are well 

 represented in both faunas, but there are no species common to the two lists. 



On the whole it seems probable from this survey of the groups that the Ceylon 

 marine fauna is more closely related to that of the Malay region and Australia than 

 to that of the Maldives or the lied Sea. 



THE FAUNISTIC CHARACTERS OF THE PEARL BANKS. 



The physical and the leading biological characters of the individual paars were 

 given in the section entitled " Description of the Pearl Oyster Banks of the Gulf of 

 Manaar," in Part I. at p. 99, and it is only necessary now to point out the general 

 faunistic features of the region as a whole. It will be remembered that it is a shallow 

 plateau, lying for the most part between the contours of 5 and 10 fathoms, and having 

 on the whole a sandy bottom. Where the ground is hard it is a modern calcrete 

 formed by the cementing together of sand and shells, and where the sand is not 



