78 PAPERS FROM THE DEPARTMENT OF MARINE BIOLOGY. 



in the U. S. National Museum, Nos. 695 and 717. Pocillopora verrucosa has larger 

 and taller verrucae and thicker branches than P. elegans. 



Dr. Wood Jones has sent "a fragment of a luxuriant colony, which when 

 alive was colored vividly pink; the exposed portions of the zooids were brown." 



Distribution. — Cocos-Keeling, Fiji Islands, general in the eastern Indian Ocean 

 and western tropical Pacific. Represented in the Hawaiian Islands by the closely 

 related, if not identical, P. meandrina Dana, the usual form of which is var. nobilis 

 Verrill. 



Pocillopora meandrina Dana. 



1907. Pocillopora meandrina Vaughan, U. S. Nat. Mus. Bull. 59, p. 97, plate 14, figs. 3, 4; plate 22, 

 figs. I, la, 2, 2a; plate 23. 



Mr. Elschner collected at Fanning Island a specimen which is essentially 

 typical Pocillopora meandrina. The branches are wide, up to 9 cm., sinuous, and 

 the summits are largely without verrucae. Verrucae, calices, and ccenenchymal 

 ornamentation as usual in the species. 



P. meandrina, as noted below, is very closely related to P. verrucosa and to 

 P. elegans. It is highly probable that they are all variants of one species. 



Distribution. — Hawaiian Islands; Fanning Island (C. Elschner). 



Pocillopora elegans Dana. 



Plate 23, figure 3, part of Dana's type; figures 4, 4a, branch of a specimen from Cocos-Keeling Islands. 



1846. Pocillopora elegans Dana, U. S. F.xpl. Exped., Zooph., p. 532, plate 51, figs. I, 10. 

 1907. Pocillopora Wood Jones, Proc. Zool. Soc. London for 1907, plate 27, fig. 3c. 

 1910. Pocillopora Wood Jones, Coral and Atolls, p. 90, text-fig. 25c 



The original specimen of Dana, probably his figured type, is in the U. S. 

 National Museum, No. 720. 



Regarding the group of forms, designated species, to which this one belongs, 

 I have said: 1 



"P. meandrina is extremely close to P. verrucosa; in calicular characters they overlap. 

 The verruca? of the latter are larger and more irregular in size, causing the corallum to have 

 a very rough, even a ragged appearance. P. damicornis, dance, verrucosa, meandrina, and 

 elegans form a series so indistinctly broken that one is led to suspect that they are really 

 continuous. It is probable that P. brevicornis and P. lobifera are a part of the same series." 



Subsequent study leads me to believe that P. damicornis, as defined by Dana» 

 is distinct, because of its longer and more tapering verrucae, but P. grandis Dana 

 and P. squarrosa Dana belong in the group. Perhaps several valid species may 

 be retained, as I am able to identify each of the so-called species, and as P. grandis 

 and P. squarrosa appear to have fairly distinctive characters. P. eydouxi Milne 

 Edwards and Haime does not belong in this group, which is characterized by having 

 inconspicuous or obsolete septa and columellas. Gardiner's reference 2 of it to the 

 synonymy of P. grandis is erroneous. P. eydouxi has conspicuous septa and a 

 well-developed columella. 



Besides the characters mentioned, P. elegans has relatively thin branches, 7 to 

 8 mm. thick just below the upper surfaces; small verrucae, about 2 mm. in diameter 

 at the base, and the summits of adult branches are naked. 



I am identifying two of Dr. Wood Jones's specimens as P. elegans; one is nearly 

 typical, the other shows the characteristic response of branching corals to surf 

 conditions. 



'U. S. Nat. Mus. Bull. 59, p. 100, 1907. =Proc. Zool. Soc. London for 1898, p. 950. 



