190 RECENT MADREPORAKIA OK THE HAWAIIAN ISLANDS AND LAYSAN. 



One specimen. Cat. No. 653, U.S.N.M., one of Danas original specimens; the 

 localitv given on the label is only " Sandwich Islands." 



f>/i»'.— Cut. No. 20!»32, U.S.N.M. 



Rewarl-fi.—The specimen selected as the type has a somewhat looser texture 

 than most of the othoi- specimens, and the syiiapticular rings are less uniformly 

 complete. 



This forma is represented by 13 specimens in all. and, as would be expected, 

 sliows considerable variation, especially in the width of the branches or plates, and 

 the amount of their fusion. The forma is based on the generally light character of 

 the corallum, the definite crown of septal granules that are detached from the wall, 

 and the more or less complete shelf formed by the peripherally placed synapticula. 



The chief difference between forma ahact/s and forma amjangcns consists in the 

 ditierence in form of the coralla; they can not be separated on calicular characters. 

 The series of specimens indicates that this difference is not of specific value. 



PORITES COMPRESSA forma TUMIDA, new. 

 Plate LXXVIXI, figy. 1, l.(. 



This forma is separatixl from forma abacus by its growth form. The corallum 

 consists of thick nodular branches arising from a common base and nuich fused infe- 

 riorly, but projecting as sht)rt stiil)s on the upper surface. Height, S.ll cm.; greater 

 distance across top of corallum, 9.2 cm.; maxinuuu length of a free portion of a 

 branch, 2 cm. The ends of the branches are rounded or somewhat flattened; their 

 bases are decidedly swollen, 2. .3 cm. or even more in diameter; diameter of ends from 

 1 to l.'.»cm. 



The calicular characters are the same as in forma nhacus. 



Locality. — •'Sandwich Islands," one of Dana's specimens. Kaneohe,Oahu; depth, 

 3 to 6 feet; received from Prof. \\ . T. Brigham. 



Type. — Cat. No. 651, U.S.N.M., United States Exploration Expedition. 



Hf'/ziar/.s. — This forma may be considered a growth form of either forma con- 

 jimgenit or forma aliacus. 



PORITES COMPRESSA forma BULBOSA Quelch. 



1886. Pontes hulbo.m l2rEi.cn, Reef Corals (.'hallenger Repts., p. 180, pi. xi, fig.s. 7, 7a. 



1901. Porites bulbosa Studer, Zool. Jahrb., Syst., XL, p. 421. 



1905. Porites haioaieims qtdnta Bernard, Porites of the Indo-Pacific Region, p. 101, pi. ix, fig. 8. 



Description. — The following is Bernard's redescription of Quelch's type: 



The corallnm forms dusters of short, thick stems, diverging fairly uniformly at angles of 4-5°; they 

 are 4 to 5 cm. long, and 2 to 2.5 cm. thick; aljout halfway up they are regularly constricted. Above 

 the constriction they swell |irior to forking. The forking tips are often quite Hat across the top. The 

 fiat top sinks in along a furrow preparatory to forking. The consecutive forkings are at short distances 

 apart. Tlie living layer is 6 to 7 cm. deej). 



The calicles are 1.5 mm. in diameter, crowded, shallow, polygonal where sharply separated l)y 

 thin walls, subcircular where the walls are thicker. The former kind of wall, with sharp median 

 ridges, occurs on the growing tops and on one side of stock, while on the other side they are thick- 

 ened evenly and uniformly into a rather close granulated reticulum, often 0.5 mm. thick, and, to the 

 naked eye, flat-topped, and making the calicles appear as sharp, circular punctures in the surface. The 

 septa are thin, tend to be lamellate, commence just below the aperture, and appear ragged and irreg- 



