212 THE VOYAGE OF H.M.S. CHALLENGER. 



rosy-red, of the polyp heads white. The prominence of the twigs causes the entire 

 colony to appear externally of a rosy-red colour. 



Habitat. — Torres Strait; depth, 8 to 11 fathoms. 



C. Divaricatse. 



The polyps on the terminal twigs are separated from one another by longer or shorter 

 distances. No sharp division between this and the preceding division is possible, as will 

 be seen from the foregoing observations. In the Divaricatse the individual polyps are, 

 however, completely separated from one another, and hence are easily distinguishable. 

 Yet even in this group indi\adual twigs occur in which two or more polyps have 

 grown together up to the tentacle-bearing heads. A generic distinction between the two 

 groups, such as Gray proposed, is on this account impossible. 



a, Umbelli/eras. — The polyp heads are arranged in umbels. 



Spongodes coronata, n. sp. (PI. XXXVIe. figs. 2a, 2b). 



A very short barren trunk divides after a short course into two divergent branches. 

 These are thickly covered with lateral branches coming off from them at right angles, 

 which, after further 'ramification, bear umbels of polyps. In the umbels the individual 

 polj^ps are free for a short space, and diverge from one another. The barren trunk is 

 very short, 9 mm. high and 1 5 mm. thick ; in spirits of wine it is soft and much shrivelled 

 and folded. From it come off two thick, diverging branches, 45 to 54 mm. in length, which 

 are covered with polyp-bearing twigs. The height of the entire colony reaches in one 

 specimen 45 mm., with a breadth of 71 mm.; in a second the height is 50 mm. and the 

 breadth 90 mm. The secondary branches come off all around the branches and are 

 thickly covered with polyp-bearing twigs, so that from the outside only umbels of 

 polyps are visible, which completely hide the ramifications. The secondary branches are 

 short, measuring about 12 mm. in length, and come off at right angles; their ramifica- 

 tions take place as follows : — Each one, after a short course of about 5 mm., divides into 

 a number of divergent twigs which finally break up into the polyp-bearing terminal 

 twigs, and these last form together an umbel. All the twgs belonging to one secondary 

 branch form a primary umbel, which may be separated from that of the adjacent 

 second;! ly branch by a small interspace. The secondary twigs bear on an average eight 

 polyps, whose short peduncles are separated from one another and diverge at acute 

 angles. 



The free portion of each polj-p is rs to 2 mm. long, and the head is 0'8 to 1 mm. in 



