ASTKyEOPOR^E GLOBULARES. 99 



Dana's figures are not very good, but, taken together with liis description, they apply to 

 this specimen ; in addition, I may add the following particulars. A well-developed 

 epitheca restrains the downward flow of the growing edge. The septa are in two well- 

 developed cycles, appearing at the margin more markedly than is typical in Astrccopora, and 

 in the depths of tlie fossa almost meeting in the centre. Young calicles in the valleys show, 

 even at an early stage, the formation of the septa, which is also not common in the budding 

 calicles of Astrccopora, which are usually smooth, membranous pits, or mere breaks in the 

 ccenenchyma. 



The surface of the corallum is indented by shallow valleys, the echinulae crowded, pro- 

 nounced, but regularly developed. They are thin, flat plates, running out distally into points ; 

 here and there they may be so twisted and joined together as to form a flaky reticulum. 

 Dana's description, " pulvinato-echinulate," is very difficult to understand ; on the other hand, 

 liis figure 3i shows a form of echinula which might perhaps represent a plate with a jagged 

 edge. The syiiapticular floors are well developed, with large pores. 



Dana's figure 3i indicates the septa meeting in the centre, but he gives nine so meeting 

 instead of six, whereas in Astrreoporans, as a rule, twelve septa are visible, of which six alone 

 approach the centre. But with regard to this point, his reference to the septa in his 

 description is so slight that we are almost justified in concluding that he laid no stress 

 upon their number. 



Dana describes and figures the living calicles with twenty-four or more tentacles in two 

 series, and of a brownish colour. 



In addition to the specimen here referred to, there is another specimen from the 

 ' Challenger ' Collection, which was placed under this heading by Quelch. As far as his 

 description goes, it appears to agree with the above. 



a. Great Barrier Eeef. Saville-Kent Coll. 



' ? b. Banda. H.M.S. ' Challenger.' 



In addition to the Astrreoporans above described, there is a young growth which difTers 

 from all the others, and which may be that of a new type. It is so young that its distinctive 

 features are not yet developed. 



It is closely incrusting, having no free edges ; the epitheca adherent everywhere to the 

 substratum. It may perhaps be a young stage in the globular method of growth. 



The calicles project as cylinders formed by the exsert septa (sometimes carrying 

 echinulic) bound together by membranous mural tissue. The septa rise right to the margin, 

 so that the aperture is often flower-like. The most marked feature of the ccenenchyma is the 

 conspicuous smooth glistening synapticular floors, continuous, and with very few pores. The 

 echinulaj are also not numerous. These features may be due to the youth of the specimen. 



The specimen was labelled A. miirioplithalma, Lamarck, but standing alone as it does, 

 unconnected by any series with other specimens, it is not possible to ascertain its true place in 

 the genus. 



a. Young specimen, sp. ?, locality not recorded. [Register No. 93. 7. 1. 19.] 



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