442 



CEYLON PEAEL OYSTER REPORT. 



culosa) is also common at Galle. But, perhaps, the most noteworthy form is the 

 remarkable, free, sand-encrusted anemone Sphenopus marsupialis, which is apparently 

 abundant at several localities in the Gulf of Manaar. 



Antipatharia are amongst the most striking forms brought up from the deeper 

 water outside the pearl banks or at Trincomalee and Galle. Most of the smaller 

 colonies obtained were new species ; but the finest belonged to the well-known 

 Antipathes abies. Several of our Ceylon species occur in the Maldives. 



The Echinodermata are an ordinary Indo-Pacific series presenting a few rarities, 

 a few novelties, and some extensions of distribution, but no other notable features. 

 It may be of interest to show the numbers of the orders separately in the case ot 

 several allied Indian Ocean faunas : 



Crinoidea . . 

 Asteroidea . . 

 Ophiuroidea . 

 Echinoidea 

 Holothuroidea 



Mergui. 



6 

 9 



13 

 6 



14 



Maldives. 



10 

 13 

 12 

 15 



Thurston 

 (Manaar). 



4 

 18 

 12 

 21 

 10 



Ceylon 

 collection. 



13 



25 

 14 

 28 

 30 



Alcock 

 (deep-sea). 



(?) few 



GO 



56 



(?)60 



(?) 20 



Probably, on the whole, the Echinodermata of Ceylon present most affinity with 

 those of the Malay region and of the Pacific, but they also show resemblances to the 

 Australian fauna. 



In turning to the Vermes, it is found impracticable to institute any comparisons 

 with other faunas in the case of the lower parasitic groups, since, in the first place, 

 from the nature of our enquiry on the Ceylon expedition it was clearly of importance 

 to collect and identify such forms as Cestode, Trematode, and Nematode parasites 

 which are very usually neglected by the general zoologist ; and, in the second place, 

 these worms seem in many cases to be confined to particular hosts, and their 

 distribution will therefore be determined by that of the Fishes and Molluscs they 

 infest. Consequently the fact that 54 Cestoda are recorded from Ceylon seas and 

 none from the Mergui or from the Maldives, must not be taken to indicate that 

 parasitic worms are more abundant in the one locality than in the others. That these 

 Platyelmian groups yielded a very large proportion of new species, no less than 17 new 

 genera and one new family, is due first to our comparative ignorance of the fish 

 Cestodes and Trematodes from tropical waters, and, secondly, to the special attention 

 paid to them during our expedition on account of their possible bearing upon the 

 problem of pearl production. 



The 10 species of Gephyrea, one new and the type of a new genus, are nearly all 

 additional records for Ceylon, and half of them are new to the Indian Ocean. Their 

 affinities seem mainly with those of the Malaysian seas to the East. 



