1 36 A. E. Verrill — Bermudian and West Indian Reef Corals. 



Some of the species of Podabacia resemble the M. elephantotus 

 rather closely in form. This is particularly the case with an appar- 

 ently undescribed species.* 



Mycedium explanatum Verrill. 



Phyllastrcea explanata Verrill, Bull. Mus. Comp. Zool., i, p. 53, 1864. 

 Plate XXIX. Figures la, 16, lc. 



Additional specimens of this species show considerable variations 

 from the type. 



The fronds may be 8-1 mm thick, but become very thin, about 

 .05 mm , at the margin. The under side is covered with unequal, 

 raised, rounded, dichotomous costse, the larger ones separated by 

 three to six smaller ones ; they are not serrulate nor echinate. On 

 the older parts of the upper side, the corallites are large, often 

 crowded, sometimes erect, but usually much inclined, mostly 8-10 n,m 

 in diameter. The septa vary from less than 12 to 18. Most com- 

 monly there are about 12 larger, subequal, very thick and prominent 

 ones, with several much thinner ones of the 3d cycle. The large 

 ones are perpendicular within, acute-angular at the summit, and con- 



* Podabacia dispar. sp. nov. Coral thin, foliaceous, in broad fronds, often 

 concave above, and very thin at the edges. Common wall thin but compact, 

 with few or no perforations, and covered with unequal, slightly raised, but con- 

 tinuous, costas ; often every 4th or 8th one is larger than the intermediate ones, 

 which decrease in size according to the cycle of the septa with which they corre- 

 spond, the smallest extending only a short distance from the edges. Their edges 

 are finely granulated, and sometimes the larger ones are sparingly denticulate 

 with very small, rough, irregular teeth, very much smaller than those of P. Crus- 

 tacea. The calicles are irregularly scattered ; the larger ones are stellate, with 

 a well developed columella, made up of irregular rough processes, sometimes 

 united into a nearly solid mass. Septa thin, in three cycles, with some very 

 thin perforated ones of the 4th cycle on the distal side. Usually there are nine 

 to twelve larger septa ; but in the outer calicles there are usually but six. The 

 principal septa are wide, rise abruptly, and form a prominent, somewhat 

 thickened lobe or angle at the summit, beyond which the edge is concave, thin, 

 finely and sharply serrate, and continuous with the long septo-costa?. The 

 prominent angle is often lacerate-toothed, but more frequently it is subentire. 

 The septo-costae are of several sizes, but generally the alternate ones are very 

 thin, deeply lacerate, and much perforated close to the edge. The synapticula- 

 are large and conspicuous. Plate xxix, tigs. ."">. ~)k. 



Diameter of the larger calicles, 4-6""" ; thickness of coral, 1.5 to 2 inches 

 from edge, 6-8 mm . 



Samoa Is. (Coll. H. A. Ward). Museum of Yale Univ., No. 6178. and Field 

 Cohunb. Mus., Chicago. 



