HAWAIIAX HOLOTHVRIANS— FISHER. 665 



irregular in contour, and with tlaelow spire ending in about eight teeth, 

 common] Y fewer. Buttons both regular and irregular, the latter most 

 numerous, the former of the usual shape with six to eight holes. All 

 buttons ai'e accumulated into rings or circles, or sometimes only 

 in groups. Suppoi'ting i-ods of i)edicels, smooth, slightly curved, 

 expanded and pei-forated at tips. Length, 80 ram. 



Localitlex. — Honolulu, reef, under rocks at low tide (11); Puako 

 Bay, Hawaii ('2). 



The variations in color and in the arrangement of pedicels have 

 already been touched upon in the diagnosis above. The tentacles are 

 very small, apparently smaller in some specimens than in oth(>rs, but 

 this is difficult to ascertain with any degree of exactness. The num- 

 ber is certainly variable, seventeen being the smallest luimber, and 

 this in a specimen otherwise quite typical. 



Calcareous ring comparatively small and delicate, the pieces being 

 rather looselv joined. Interradiul pieces rather wider than radial, or 

 at least as wide, but of the usual shape. Each radial piece is pro- 

 longed slightly farther forward than the interradial and has the usual 

 roundish incision. The anterior edge of the interradialia has a single 

 tooth. Polian vesich^s two, rather long. Madreporic canal small, 

 single, free, on right side of mesentery. No Cuvierian organs. 

 Respiratory tree with left])ranch in connnunication with rete mirabile 

 of intestine. The gonad in one specimen is large and the strands have 

 a moniliform appearance. 



The most characteristic feature of the deposits is the accunudation 

 of the buttons in small circles or circular groups, which may be seen 

 with a hand lens in an ordinary alcoholic specimen. Here the}^ appear 

 as small whitish spots. The diameter of such a circh^ or group varies 

 from 0.13 to 0.3 mm. The ])uttons are very fretpiently incomplete; 

 usually more or less irregular even if complete, when they are of the 

 usual form, with from live to eight holes in tw'o rows. When the 

 buttons are fairly regular, with six holes, the median pair is the 

 larger. Rarely a button has two or three irregular, illy defined prom- 

 inences on the surface. An average button measures 0.065 mm. in 

 length; many are smaller than this, being only 0.045 mm.; some are 

 as long as 0.08 mm. and appear to be confined to the ambulacral 

 appendages. The irregularity of some buttons is enhanced bv a 

 slight twisting on the long axis. Some specimens appear to have a 

 greater proportion of complete buttons than others, while in some 

 individuals the proportion of regular buttons is greater. The form of 

 the tables is better shown bj^ ligure than d(\scription. The disk is 

 rather variable as to size, ranging from 0.054 to 0.085 nun. in diameter. 

 The edge appears always to be spiny. As a rule the disk is rather 

 stout and either has four perl'orations, one at the base of each spire 

 support, or eight when the disk is larger and more nearl}" circular. 



