OF THE MERGUI ARCHIPELAGO. 



23 



with the types in the British Museum, and there is no doubt that 

 Phymastrcea irregularis, Dune., which I described in the Proc. 

 Zool. Soc. 1883, p. 406, is a Mergui form. P. aspera, Quelch, which 

 will shortly appear described in the ' Challenger ' Report on the 

 Reef Corals (p. 105), is also a Mergui form. Its first discovery 

 was at Banda. 



The Solenastraean subgenus QuelcJiia has occasional fissiparous 

 calices, and is a characteristic form from Mergui. Plesiastrcea 

 indurata, Verrill, was described by Yerrill from the Loo Choo 

 Islands(Proc. Essex Institute, ser. 2, vol. v. 1867, p. 35, pi. 2. fig. 7). 



The Balanophyllia is a well-marked species, and the row or 

 crown-like series of swollen tertiaries resembles one consisting of 

 pali. The small and young forms show this peculiarity also, and 

 their septal number is of course lower. 



The Dendrophyllia is a common form at Mergui, and, as the 

 specific name implies, the colony is stunted, and resembles a 

 bunch of compressed buds without a definite stem. It is a very 

 exceptional species of a very variably shaped group. The sub- 

 genus Coenopsammia is represented by an interesting species, and 

 it is not without its affinity with C. coccinea ; but the small and 

 variably shaped columella and the septal number constitute, 

 besides the colour, specific distinctions. The variability of the 

 corallites in the small colonies of this species is very suggestive. 



VerriU's species Astropsammia Pedersoni, which was first found 

 in the Panamian province of ~W. America, occurs at Mergui, and 

 there is no doubt that the distant localities have their simple 

 corals closely allied and some of the colonial also. 



The collection of species of Madrepora is very considerable, and 

 their variability, owing to the conditions under which the forms 

 grew, has given much trouble in classification. The only form 

 about which I have some doubt I have classified under JI. gracilis, 

 Ed. & H. The description given in Hist. Nat. des Corall. vol. iii. 

 p. 147, is conveyed in two lines and with a reference to another 

 species. The large tubulo-nariform calices are very characteristic 

 of the Mergui form. A species, M. ertbripora, also with nariform 

 calices, is stunted, and shows some evidence of having had the 

 same occasionally slightly saline water to live in as is the case 

 w r here the type of Dana was obtained in Fiji. Some of the 

 species found at Mergui have a Eed-Sea habitat, and others 

 belong to the Pacific fauna. 



The genus Po rites flourishes at Mergui, and there is a large 



