MUSEUM OF COMPARATIVE ZOOLOGY. 11 



deep reddish-brown, and the brachia of a flesh-color. The latter were in 

 the shape of a horseshoe, with no trace of a median lobe. They were 

 close set and marked with transverse lines, as in T. cubensis. The mem- 

 brane which covered the viscera was covered internally with irregular 

 hyaline spots with well-marked boundaries, which no doubt are the limits 

 of the lacunar channels of circulation. The mantle was quite transparent, 

 with a brownish edge, and in each of the internal channels, corresponding 

 to the ribs of the outside of the shell, was a single bristle, composed of 

 longitudinal fibres of chitine, without any of the transverse markings 

 which are seen in the seta? of the adult. The extreme tip of the bristle 

 alone protruded from the mantle, and its inner extremity was slightly bul- 

 bous. It was of a glistening yellow color throughout. In those adults 

 which I examined there were only five or six of these setae in each mantle 

 lobe. These specimens were obtained off Havana, in two hundred and 

 seventy fathoms water. 



The very extraordinary manner in which all the soft parts were crowded 

 and crammed with masses of calcareous spicula? defied my best efforts to 

 obtain any very satisfactory results from the two or three alcoholic speci- 

 mens at my command. A flocculent mass of white matter resisted the 

 action of acid, and filled all the interstices of the membranes, so as to ren- 

 der them quite opaque. The genitalia were in such a condition that they 

 were quite invisible, and the animals appeared to be out of season. The 

 intestine was cylindrical, and ended much as it does in T. ccqiut-scrpcntis. 

 The mouth was surrounded by a dark-brown line. There were no struc- 

 tures above and behind the mouth, such as are described as existing in T. 

 cubensis. The attached extremities of the muscles were of a very bright 

 red-brown. Most of the specimens were overgrown with a tough, spongy 

 organism, like velvet. The peduncle is white, slender, and exceedingly 

 long, the exposed portion sometimes equalling in length one third of the 

 shell. A brownish tinge pervaded all the tissues of the adult. Transverse 

 markings were noticed on the brachia, as described in other species by 

 Hancock. 



One specimen growing on a rock which had become covered with 

 sponge afforded an interesting observation. The peduncle was exceed- 

 ingly long, and, on cleaning off the sponge, it was seen that the creature, on 

 the growth of the sponge toward it, had apparently lengthened its peduncle 

 to get out of the way ; and while the original attachment still remained 

 (and the glossy opalescent color of that part of the peduncle testified to 

 its healthy condition), somewhat farther on, nearer the shell, a second at- 

 tachment of the peduncle had taken place by the outgrowth, from the 

 underside, of a bunch of cylindrical rootlets, exactly resembling the attach- 

 ment of an ivy to a stone. The under side of the peduncle and the root- 



