240 BULLETIN OF THE 



phore of this species, however, was spherical, and not elongated like that of 

 C. Murrayana. The position of the pneumatopore was at the centre of a 

 pigmented iris-like spot. The contractions and expansions of this iris-like 

 portion caused the pneumatopore to be opened and closed like the pupil of 

 the eye, and thus the pneuniato-sac might be freed of its contained gas. Eight 

 bunches of hyposistic villi projected as branching sac-like protrusions from the 

 entodermal wall of the pneumato-sac into the cavity of the pneumatopore. 



An excellent description of the construction of the pneumatophore in the 

 Rhizophysida) has been given l)y Gegenbaur (Ban der Pneumatoi)horen, Zool. 

 Anzeiger, Jahrg. X., pp. 511-529). The hydrosoma bore only feeding polyps 

 and tasterns. These appendages grew out from one side only of the hydro- 

 soma, and were thus arranged vertically under one another, although when the 

 animal was contracted, and the hydrosoma was twisted, it gave them the ap- 

 pearance of being spirally twirled. The appendages of the hydrosoma first 

 make their appearance just under the pneumatophore, and as the hydrosoma 

 increases in length they are carried downward (see Piute III. Figs. 1,2). The 

 feeding polyps appear iirst, then the tasterns make their appearance a little far- 

 ther down the hydrosoma as slight protuberances just above the place of attach- 

 ment of each polyp. As they increase in age, they begin to show the secondary 

 filaments (see Plate III. Figs. 1, 2). The secondary filaments are fine hair-like 

 structures terminating in a bunch of neraatocysts (see Plate III. Fig. 4). Two 

 sets of muscles are found in the hydrosoma and pneumatophore, — a peripheral 

 longitudinal set and a deeper-lying circular system. The contractions of these 

 two systems are very vigorous, and allow the animal to elongate itself enor- 

 mously, so that it resembles a delicate thread of spun glass, bearing at regular 

 intervals little bunches of glass beads, or it may draw itself up with great rapid- 

 ity into a closely wound helix. The mouths of the feeding polyps often exi)and 

 themselves out into a trumpet-shape. The hydrosoma is slightly yellowish in 

 color, and the ectoderm of the pneumatophore is of a delicate rosy tint. 



We captured a number of specimens, some from the Bahama Banks, but most 

 of them in the Gulf Stream ofi" the northern coast of Cuba. They came up cling- 

 ing by means of their tasterns to the wire rope of the Tanner tow-net. One 

 specimen was found fastened to the rope when 180 fathoms of it had been drawn 

 in ; another, captured in the Gulf Stream, was found in the upper portion or 

 the Tanner net after it had been towed at the depth of 150 fathoms. Evi- 

 dently this specimen was then swimming within this depth of the surface. The 

 animals were extremely sensitive to touch, and, contracting themselves into a 

 tangled mass, they very soon began to throw off their feeding polyps, after which 

 thev died. Figure 2, Plate III., is an enlarged view of a small individual, the 

 actual size being indicated by tlie scale which accompanies it. 



