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Systematic Position

species, found, brazilian and comatulids

SYSTEMATIC POSITION.

Comparison of the comatulids taken at Tobago with a considerable series of specimens from several stations on the Brazilian coast, south of the Amazon, shows that they are unquestionably identical. For this Brazilian species, Mr. A. H. Clark has revived an old name of Gay's, pieta, regarding it as "a perfectly good species," "most obvi ously differing from carinata in the greater length of the outer cirrus segments" (Proc. U. S. Nat. Mlus. 1911, vol. 40, pp. 35, 36). On com paring the Brazilian and Tobagoan material with specimens from Mauritius and Zanzibar, I was utterly unable to detect any differences, either in the cirri or in any other characters. On writing to Mr. Clark of my difficulties, he very kindly replied that while the species of Tropiometra are very difficult to distinguish, he finds "no difficulty in distinguishing" the group in which he places pitta from that in which he places carinata, "by the difference in length of the outer cirrus seg ments." On receipt of his letter, I went over the cirri again, but I found myself absolutely unable to detect the difference named. I have therefore very reluctantly reached the conclusion that I can not recognize pieta as a valid species, but must designate my Tobagoan comatulids by their old Lamarckian name.

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 Coraina 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.