91 



end. It gives off' a few stolons at its base, is granular in appearance and some- 

 what leathery in texture. 



The polyparium is imperfectly oval in shape, with the long axis at an angle 

 to the stem, and is slightly flattened in one plane. The surface is well developed 

 and almost continuous on one side, but on the other it is irregular. The 

 branches are almost uniform in length, rounded and thick, and give rise to 

 the polyp-bearing twigs by repeated divisions. The 

 stem rises to the tip without any division. 



The polyps are arranged in groups of four to 

 eleven, and these again are arranged into larger groups, 

 which have a flat surface due to the polyps in a group 

 all reaching the same level, and thus all reaching the 

 surface of the polyparium. They are low and round, 

 being 056 mm. high and from 048 to 0'56 mm. broad. 

 They are placed at an obtuse angle on stalks which vary 

 greatly in length — from 0'16 to O'o mm. The spicules 

 are arranged as follows : There are a few horizontal 

 rows of spicules and above these there are eight double 

 rows of three pairs of converging spicules, the upper- Fig. 45. D. brachycaulos. 

 most pair of each row slightly larger than the others, 



and projecting slightly beyond the polyp. They are flat spindles with few 

 projections and measure on an average 0*4 mm. in length and 0048 mm. in 

 breadth. 



The Stutzbiindel consists of a number of spindles which measure from 

 0'(j4 to 1'4 mm. in length, 1;)ut scarcely project beyond the polyp-head. 



Cortical spicules : [a) The stem shows straight or curved spindles and roughly 

 spindle-shaped forms thickly covered by numerous smooth to rough spines ; 

 these forms are blunt at the ends or show division into two or three prongs, 

 which either spread out or lie in close contact with one another throughout 

 their length. The spicules vary from 024 to 112 mm. in length, and from 

 0064 to 0'24 mm. in breadth. They are arranged in a very irregular manner 

 on the stem and principal branches, these parts acquiring an appearance sug- 

 gestive of a heap of pins, but they tend to run more parallel to the length of 

 the secondary branches and twigs. 



(//) In the stalk the spicules are spindles, imperfect clubs, three-, four- and 

 five-rayed forms, all of which are thickly covered with prominent simple to 

 branched spines. In addition there are a few less complex irregular spindles, 

 rods and stars. Spindles vary in length from 0"16 to 0"47 mm. and in breadth 

 from 0'016 to 0'08 mm. Clubs measure up to 0'48 mm. in length and 0"12 mm. 

 in breadth. Rayed forms may measure 048 mm. from tip to tip. 



Canal-wall spicules : {(t) In the stem there are spindles from 0*56 to 



