A. H. CLARK: THE CRINOIDS OF THE INDIAN OCEAN. 11 



(Comastrocrinus) appears at the Andamans, and is the only stalked crinoid known 

 from the region. This district limits the westward extension of the Zygometnda\ 

 the Pontiometridse , the genus Mariameira oi the Mariametridte , the Calometridae , 

 and the Zenometrinae ; of the family Zygometridse the genus Zygometra is found 

 in the Mergui Archipelago, and EiuUocrinus in the Andamans; Pontiomeira occurs 

 in tJie Mergui Archipelago, while Psaihyrometra and Neometra are known from the 

 Andamans. A significant feature is the absence of the family Apiocrinidse, and 

 of tlie following 18 genera, which are found no further west: Comatula, Coman- 

 theria,'Catoptometra, Aslerometra , Stenometra, Stirenietra, Parametra, Glyptometra, 

 CJilorometra, Paecilometra, Charitometra , Strotometra , Compsometra, Toxometra, 

 Balanometra , Thysanonietra, Hypalocrinus, and Metacrinus, as well as of the large 

 species of Tropiometra. 



The general trend of the East Indian fauna is now directly across the Bay 

 of Bengal to Ceylon, the coast line to the north of the mouths of the Irrawaddy, 

 and to the north of Ceylon being very poor in crinoids and supporting only a few 

 common and very wide-ranging species, or representatives of a few very common 

 and wide-ranging genera. 



About the coasts of Ceylon and in the Maldive and Laccadive Archipelagoes 

 are found 30 species of crinoids representing 21 genera and nine families (Comas- 

 teridaj— Comct^e^fo, Capillaster, Comissia, Comaster, Comanthina, Comanthus 

 (Vania group) ; Himerometridse — Amphimetra, Himerometra, Heterometra ; Stepha- 

 nometridse — Stephanometra; Mariametridse — Dichrornetra , Selenemetra ; Colobo- 

 metridfe — Cenometra, Decametra, Colobometra, Oligometra; Tropiometridse — 

 Tropiometra; Thalassometridaj— P^eromcira ; kntedonidsi—Mastigometra, Tricho- 

 metra; Fentsiciinitidas— Comastrocrinus); besides these, 11 genera representing 

 three additional families occur both to the eastward and to the westward of Ceylon 

 and undoubtedly exist there; these are, the Bennettia group of Comanthus; 

 Craspedometra, Cyllometra, Thalassometra, the Charitometridae {Pachylometra) , 

 and Peromeira; and Cydometra, Thaumatomelra, Bathymetra, the Pentametro- 

 crinidffi (Pentametrocrinus), and the Bourgueticrinidae (Rhizocrinus); a single 

 species, Himerometra persica, is known from either side of Ceylon but has not yet 

 been found there. Adding these, the crinoid fauna of Ceylon may be considered 

 as made up of 32 genera, representing 12 families. 



Ceylon is the only definitely ascertained habitat of the genus Masligometra 

 which, however, undoubtedly occurs to the eastward. Including the Maldive 

 and the Laccadive Islands, Ceylon marks the furthest westward extension of the 

 genera Comanthina, Pterometra and Comastrocrinus , and all of the very large 

 highly multibrachiate species of all genera such as Comatella, Capillaster, Comaster, 

 Comanthina, Comanthus, Amphimetra, Himerometra, Heterometra, Stephanometra 

 and Cenometra, and of the large species of such genera as Colobometra and Oligo- 

 metra. 



Like the fauna of the Andaman Islands and the Malay Peninsula, that of 

 Ceylon is not characterized by a development of endemic or curious sporadic 



