1 88 Papers from the Marine Biological Laboratory at Tortugas. 



between the Bugula and Stirparia types of stems. From the lower stem 

 zooecia arise numerous, strong, radical fibers. 



The ordinary zooecia, which are arranged biserially, are long and slender 

 and expand but little toward the tip; the frontal aperture extends almost 

 to the base and faces somewhat toward the axis of the branch; a strong 

 spine is situated at the distal outer edge; near the distal end, at the point 

 where the outer wall curves farthest over the frontal area, is situated a 

 short, stout avicularium with a strongly decurved beak; the avicularium is 

 set upon a stalk so short as to be almost wanting. 



The ooecium is hemispherical, very small, and set very low down, par- 

 tially hidden by the spine, so as to be very inconspicuous; it is thin and 

 transparent, with a slightly arched aperture. Many of these contain em- 

 bryos in various stages of development. 



Taken at i8 fathoms on a bottom of coral mud, several colonies attached 

 to shell fragments; the largest 2.5 inches in height. Small fragments were 

 also found decorating the legs of crabs {Hyas sp.?) at the same depth. 



Bugula caraibica Levinsen. 



Levinsen, 1909, p. 104, pi. m, figs. 2A-2N. 



This species, recently described from St. Croix, Danish West Indies, is 

 common at the Tortugas on the piles of the government docks, and colonies 

 1.5 inches high were taken on the bottom of a skiff which had been in the 

 water only from May i to June 23, 1908. 



It is one of the most conspicuous species of the region, growing in loose 

 tufts of a fine purple color to the height of 4 to 6 inches. Levinsen does not 

 recognize Stirparia as a separate genus, but if the species with a jointed 

 stalk are to be separated, caraibica will fall in that genus, 



Bugula armata Verrill. (Figs. 4 and 5.) 



Verrill, 1900, p. 588 {Bugula [Caulibugula] armata n. sp.). 



Verrill has described from 

 Bermuda a species which I 

 take to be the same as one 

 occurring at Tortugas. His 

 description is as follows: 



A much more delicate, white 

 Bugula, consisting of diverging, fan- 

 like branches attached to the alter- 

 nate sides and to the tip of slender 

 jointed stems, sometimes having 

 alternately a long joint and a very 

 short joint, but more frequently the 

 short joint is lacking and the end of 

 the joint is swollen, as in Stirparia. 

 There are usually 2 or 3 annulations 

 at the base of each main branch and 

 these arise just below the internodes. Many of the cells have a slender, distal vibraculum or 

 sometimes two. It should doubtless form the type of a new genus or subgenus {Cauli- 



FiG. 4. — Bugula armata Verrill. Modified zooecia at base 

 of branch, showing arrangement of spines and position 

 of avicularia. 



Fig. S- — The same. At tip of same branch, showing character 

 of spines and position of avicularium. 



