86 RECKNT MADREPORAIUA OV THK HAWAIIAN ISLANDS AND LAYSAN. 



Corallu.n fornun^: ratluT Ui.«.. .'Uunps (15 .■>.,. ,.,• ,n.,r. in dianu.ter); branches compressed, separate. 

 Septa wi'U (levoli)i>e(i. 

 Coluniolla styloid. 



Verrucii' iHT|..T..iicnlar to snrfac.- of bnin.'h..s and unif..nnly distnlmted 



3. P. modumanensU. 



Verruciu am)re,ssed, often forming carinie, irregularly distributed 4. P. liguhda. 



, , . 5. P. frondosa. 



\ errucie ob.solete •' 



Septa rudimentary or obsolete, columella absent- <ir a central compressed dome. 



Verrmw, usually uniformly distributed, regular or rather regular in size.... 6. P. meandrma. 



Branches n.eandroid, summitsnaked 6n. P. meandrma typical. 



Branches comprei^sed, summits verrucose 66. P. meandrma x&t. notnlis. 



Itranches with .listally swollen yerruca' 6c. P. meandrina w&T. tuberosa. 



Corallum glomerate-.-espitose, massive at Ijase, \vith irregularly Hattened and compressed branches 



above. .><epta obsolete, .■olumella styl.ud 7. P. infonms. 



I. POCILLOPORA CESPITOSA Dana. 

 Plate X, tigs. 1, In, 2, 2a; Plate XI, figs. 1, 2 (typical form). 

 1846. PoriUopora cesjnlom Dana, Zooph. Wilkes E.xpl. Exped., p. 525, pi. xLi.x, figs. 5, 5a. 

 184(i. PiinUopura hrerirornis (part) Dana, Zooph. Wilkes Expl. Exped., p. 526. 

 1860. Pocillopom reapitoKii Milne Edwards, Hist. Nat. Corall., Ill, p. 303. 

 1869. Poi-illojiora ai-Kpilosn Verrill, Proc. Essex. Inst., VI, p. 91. 

 1886. Pocillopom (•expilom Quelch, Reef Corals, Challenger Repts., p. 66. 

 1901. PoriUopora cxspitosa Studer, Zool. Jahrb., Syst., XL, p. 399. 

 Original description.—Thisis asioWows: 

 Low and even-topped cesi)itose, much and crowdedly branched, branches much shorter than in 

 the acuta, tortuous, 2 to 3 lines thick, and stouter at base; summit branchlets verruciform. 2 lines 

 long, and often subacervate. Corallum having the cells large ( i a line broad), and without star or 



columella. 



******* 



The clumps are neat, low-convex, and much branched; the branches are crowded to within one- 

 third to half an inch of one another, and are mostly a fourth of an inch or less in thickness. The cell is 

 large and shallow, and has a flat bottom; those low on the stem are rather distant, and a delicate line 

 may be traced around them, as in some Seriatopone. The species most reseml)les the damiconus, of 

 which I had considered it a dwarf variety; but it is a much neater and more slender species, and has 

 larger cells. 



As this species shows a bewildering amount of vaii;ition, apparently its charac- 

 ters can !)(' t)cst expressed by describing the typical specimens and then indicatino- 

 the lines along which variation takes place. In addition to the typical form, three 

 varieties are recognized. After describing these and showing how the}' intergrade, 

 an attempt will be made to point out the characters that bind all together. 



I a. POCILLOPORA CESPITOSA (typical). 

 Plate X, figs. 1, la, 2, 2a; Plate XI, tigs. 1, 2. 

 I am referring 21 specimens to tj'pical P. ce^pito.sa, although they show consider- 

 able variation. Of these specimens. 2 are original sp(>cimens of Dana, 7 had sub-<e- 

 qnently l)eeii added to the United States National ^Museum collections, 7 were collected 

 by the Alhatrosn in 1902, and 5 were sent me by Dr. W. T. Brigham. 



The general form of the colony is as Dana desi-rit)cd it. However, the distance 

 apart and the attenuateness of the summit branchlets varies considerably. In one 

 specimen, No. 2184," some of these may be nearly I cm. long and 3 mm. in diameter. 



"These numliera refer to United States National Mu-seum Catalogue. 



