358 BULLETIN 100, UNITED STATES NATIONAL MUSEUM 



TUBUCELLARIA EXILIS, new species 



Plate 44, figs. 5-9 



Description. — The zoarium is jointed; the chitinous articulation of 

 the segments is complex; the segments are long, thin, more or less 

 curved, little narrowed at the base. The zooecia are distinct, sepa- 

 rated by a furrow of little depth, elongated, fusiform; the frontal is 

 little convex, covered with linear, very elongated tremopores; the 

 spiramen is placed at the superior third of the zooecial length. The 

 apertura is placed at the bottom of a short peristomie; the peristome 

 is thin, orbicular, little salient, nonoblique. There is frequently a 

 large radicular pore adjacent to the peristome. 



ir , ~ - • \Lz = 1.00-1 .20 mm. 



Measurements. — Zooecia \- 



lZs^O.30 mm. 



Diameter of peristome, 0.16 mm.; length of segments, 10.00; 

 and diameter of segments, 0.54. 



Structure. — The basis ramae is complex; the principal bundle of 

 articulation issues from a much larger aperture (0.12-0.14 mm.); it is 

 surrounded by thinner bundles issuing from an adjacent ordinary 

 aperture and from some tremopores surrounding the apertura; the 

 latter are very inconstant and are frequently lacking. The segments 

 are replaced sometimes by ascending radicels as is visible on our figure. 

 Affinities. — This species resembles Tubucellaria cereoides variety 

 gracilis, but is thin and lean. The dimensions approach very closely 

 to Tubucellaria Zanzibar ensis Waters, 1907, but the present species 

 differs in its short peristome and in its different articulations. It 

 differs moreover from Tubucellaria filiformis new species in its non- 

 oblique peristomice, in its larger dimensions, in its salient spiramen 

 and in its long tremopores. 



Biology. — Our specimens from the Sulu Archipelago were living but 

 they did not bear ovicells. Some are attached by chitinous joints, 

 but we have no entire colony and even are ignorant of the mode of 

 fixation. 



Occurrence. — 



D. 5137. Jolo Light, Jolo; 6° 04' 25" N.J 120° 58' 30" E.J 20 



fathoms; S. Sh. 

 D. 5147. Sulade Island, Sulu Archipelago; 5° 41' 40" N.; 120° 



47' 10" E.; 21 fathoms; co. S., Sh. 

 D. 5151. Sirun Island, Sulu Archipelago; 5° 24' 40" N.; 120° 



27' 15" E.; 24 fathoms; co. S., Sh. 

 D. 5478. Tacbuc Point, Leyte; 10° 46' 24" N.; 125° 16' 30" E.; 

 57 fathoms; Sh. 

 Cotypes.— Cat. Nos. 8139-8141, U.S.N.M. 



