114 Papers from the Department of Marine Biology. 



HABITAT. 



We first found Tropiometra in Buccoo Bay, where it occurs in water 

 from a few inches to several feet in depth at low tide; indeed, at the 

 lowest tides some individuals are probably out of the water, in part 

 at least, for a short time. The bottom which they frequent is made 

 up largely of Porites fragments, usually more or less covered by a 

 growth of Corallina and Halimeda. Scattered over it there is also a 

 sparse growth of short eelgrass (Zostera). As a rule the comatulids 

 hold themselves in an erect position by means of their stout cirri, which 

 are customarily grasping a bit of Porites. Sometimes the body is more 

 or less completely shaded by a clump of eelgrass or seaweed, but this 

 is not usually the case. Generally the individuals are solitary, but 

 occasionally five or six may be found about a single clump of Porites 

 or of eelgrass. They are not really abundant, but twenty or more 

 may be gathered in half an hour or less. Now and then we found 

 individuals living underneath slabs and large fragments of coral; this 

 was particularly true on Buccoo Reef, where, later, a number of speci- 

 mens were discovered. All were in shaded places, suspended arms 

 down, and not in the usual erect position. 



COLOR AND SIZE. 



The first specimens of Tropiometra seen appeared to be uniformly 

 dark purple, purplish-brown, reddish-brown, or bright brown, but a 

 closer examination showed that uniform coloring was very rare. 

 Almost always a longitudinal dorsal stripe on each arm, or transverse 

 bands of more or less width, or both, are present. The color of these 

 markings is yellow of some shade, often dull and buffy, but not rarely 

 quite bright. In some individuals the pinnules are also cross-banded 

 with yellow, and the distal pinnules may be uniformly brownish yellow. 

 The cirri are yellow brown, at least dorsally, but are often more or less 

 dusky or purplish on the oral surface; in nearly all individuals, how- 

 ever, both young and old, the terminal two or three segments (except 

 the claw) have a dusky spot on the oral side. This marking seems 

 to be a very constant character in Tobagoan specimens. Occasional 

 individuals are found in which the pinnules and dorsal side of the arms 

 are plenteously besprinkled with silvery-white, giving them an excep- 

 tionally handsome appearance. 



All of the small specimens found were brownish-yellow or bright 

 brown, more or less marked and banded with purple, and this general 

 coloration is not rare in adults, particularly in those found under slabs 

 of rock on Buccoo Reef and in similar shaded places. Some of these 

 individuals were very handsome in their brilliant array of purple and 

 gold, and it was hard to believe they were really identical with the 

 dull-colored specimens from the shallows of Buccoo Bay. A natural 



