444 CEYLON PEARL OYSTER REPORT. 



of affinity with other regions. The Cirripedia are a somewhat cosmopolitan group, 

 but our Ceylon assemblage shows some affinity with the Red Sea and the Australian 

 faunas. 



The Amphipoda and Isopoda were both large collections containing a number of 

 new forms. The individual animals in both were of small size compared with those 

 from temperate and polar seas. In the Amphipoda 85 species gave 37 new to science, 

 requiring the formation of six new genera. A few of the species extend to the Red 

 Sea, the West Indies, the Malay Archipelago, and the Pacific, seven are found in the 

 Australian fauna, and ten in the Mediterranean. In the case of the Isopoda, out of 

 34 species 14 proved to be new, requiring three new genera and two new families. 

 Here, also, there is indication of Australian affinities, and two species extend to the 

 West Indies. 



The Cum ace A, being a comparatively unknown group, are all new records tor the 

 Indian Ocean, and out of the 16 species nine are new and one has required a new 

 genus. We do not know enough of the distribution in this case, or in that of the 

 Stomatopoda and Schizopoda, to make comparisons with other seas. 



In the Macrura, out of 53 species, three of which are new, a large proportion, 24, 

 extend into the Pacific, 10 are common to the Malaysian fauna, and 10 also reach the 

 Australian seas, nine are found in the Atlantic, four in the Red Sea, three in the 

 Mediterranean, and one in the West Indies. 



The Anomura, as a group, have, to the collector, the appearance of being very 

 abundant, but that is due chiefly to great numbers of a few common species. At 

 Galle, and at Trincomalee, ten times the present collection might easily have been 

 made without adding to the number oi species. Out of 4 8 species collected only two 

 are new, and they present no features of special interest. Alcock has pointed out 

 that the littoral Paguridse of the Maldives and India are Indo-Pacific forms, while the 

 sub-littoral forms of Indian seas are most closely related to those of the West Indies. 



The Brachyura form a very large and interesting assemblage, in which only a 

 comparatively small proportion, 15 out of 208 species, have proved to be unknown, 

 but three of these are so remarkable as to require new genera. About 60 per cent, of 

 the species are new to the Ceylon fauna, and 35 per cent, extend to the Maldives. 



The Pantopoda and Hemiptera both contain new forms that seem to be common 

 at Ceylon, but call for no further remark. 



The Mollusca are an ordinary Indo-Pacific assemblage, most of which have been 

 made known in the past from shell collections. The chief novelties are naturally in 

 those divisions of the group which have not been studied by conch ologists. The 

 Nudibranchs present us with at least nine new species in 30 collected, and, in 

 addition, there are some small Eolids and Dotos undetermined that show, at least, 

 that these families are not so rare as was supposed in tropical seas. The Opistho- 

 branchs, as a whole, show some affinity with Red Sea and Mediterranean forms, but 

 still more with the Pacific and Australian faunas. Two new species of Pelecypoda, 



