386 THE GORGONIANS OF THE BRAZILIAN COAST. 





mm. 



* 



In longitudinal, tangential sections the calicles are round, 0.50 to 75 

 in diameter, often separated by intervals of 1 to 2 mm. or more; sometimeslT 

 only a thin septum. The intervening ccenenchyma is filled with numerous small 

 pores and tubules, running in all directions, and separated by narrow, spiculos 

 intervals, so that they produce a sponge-like or subcancellated structure. 



Some of these tubules terminate at the outer surface in small pores often 

 situated in small pits, which may function as siphonozoids. The ccenenchyma 

 between the ducts is densely filled with small spicules of various shapes. The 

 outer thin, superficial layer is more dense and is largely made up of very small 

 granule-like spicules in the form of heads, double-heads, double-rosettes, etc. 

 closely packed. 



The prepared spicules are smaller than in any of the preceding species of the 

 genus. The most abundant of the larger spicules are regular strongly warted 

 spindles and double-spindles, some rather short and blunt, others more slender 

 and acute, and also tripartite forms and irregularly twinned spicules. The more 

 regular crosses are not numerous, and most have rather narrow, blunt, or even 

 clavate, often unequal rays, but some are very symmetrical. 



Small spicules in the form of double-heads, double-rosettes, small crosses, 

 etc., are very abundant. 



The larger double-spindles measure 0.42 X 0.11; 0.35 X 0.14; 0.34 X 0.11 

 0.31 X 0.12; 0.30 X 0.13; 0.26 X 0.11; 0.35 X 0.13; stout spindles, 0.27 X 0.11 

 0.21 X 0.12; tripartite forms, 0.30 X 0.28; 0.30 X 0.20; crosses, 0.35 X 0.30 

 0.34 X 0.22; 0.30 X 0.22; 0.29 X 0.26 mm. 



In general external appearance this species closely resembles some of the 

 West Indian varieties of P. dichotoma, but the spicules are different. 1 



Abrolhos Reefs. Coll. C. F. Hartt, 1867. Type, No. 1598. 



Plexaurella pumila Verrill, sp. nov. 



Plate XXXI, figure 5 (general figure of No. 4502, reduced). Plate XXXII, 

 figure 8 (piece of a branchlet, enlarged). Plate XXXIV, figure 2 (spicules). 



Coral of the type, low with short, irregular, crooked, dichotomous branches, 

 not in a plane, forming a shrub-like tuft. The branching begins close to the 

 base, and there is a secondary stalk with three branchlets, arising from the base. 

 The main stalk divides at three and four stages, at intervals of about 10 to 20 

 mm. ; often less. The longest terminal branch is 48 mm. long; most are 20 to 40 

 mm. ; diameter, 6 to 8 mm. ; total height, 95 mm. ; breadth, 90 mm. The branch- 

 lets are often a little enlarged at the tips, which are bluntly rounded. 



The calicles are rather large, pretty evenly disposed over the whole surface 

 and rather closely crowded, being nearly or quite in contact in many places. 

 They are only slightly raised, sometimes in the form of low, rounded verrucse, bu 

 more often with merely the margin a little raised. The apertures are mostly 



1 For good figures of the spicules from the original types of P. dichotoma (Esper) and P. <w<W s 

 (D. & M.) see Verrill, Trans. Conn. Acad. Sci., vol. XII, pi. 36a, figs. 1, 2, 1870. 



