136 



BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



as the thorax, which arises from the posterior part of the dorsal side 

 of the thorax, and in most zooids is directed forward (fig. 89), but 

 it occasionally extends out at right angles to the length of the body. 

 A long narrow neck which often becomes much bent and contracted 

 in preservation connects the thorax and the abdomen. Vascular pro- 

 cesses of the abdomen were not noted. 



Mantle musculature consisting of a superficial la} 7 er of narrow, 

 rather widely spaced bands underlaid by slender groups of transverse 

 fibers so closely placed as to form a nearly continuous sheet, which 



@ 



also covers the atrial and branchial tubes. Pos- 

 terior to the thorax the transverse muscles prac- 

 tically disappear, though the longitudinal muscles 

 are conspicuous even on the abdomen; the bands, 

 however, spread out and unite with each other to 

 form a practically continuous sheet. 



Tentacles apparently few; only two sizes were 

 certainly demonstrated. 



Dorsal languets small, arising from the trans- 

 verse vessels of the left side the width of about 

 four stigmata from the median dorsal vessel. 



Branchial sac with only three rows of rather 

 long narrow stigmata, with at least 18 or 20 

 stigmata in a row on each side. Near each end 

 of each roAV the last few stigmata become succes- 

 sively shorter. 



Stomach short and rounded, smooth-walled; 

 margin of anus somewhat two lipped. 

 The reproductive organs lie beside the intestinal 

 loop and are of the t}^pe usual in this family. The 

 male glands numbered 15 to 20 in zooids of the 

 specimen from Bantayan mentioned below. Re- 

 productive organs not developed in the Albatross 

 specimens. 



The only colonies containing well-developed zooids are two (No. 

 126) (Cat. No. 6029, U.S.N.M.), from station D5139 (off Jolo Light, 

 Feb. 14, 1908, 20 fathoms, coral sand). 



Large colonies, containing very few zooids, except some in a de- 

 generate condition, were obtained (No. Ill) (Cat. No. 6030, 

 U.S.N.M.), at station D5145 (near Jolo Light, Feb. 15, 1908, 23 

 fathoms, coral sand and shells) and (No. 119) (Cat. No. 6028, 

 U.S.N.M.), at station D5160 (off Tinakta Island, Sulu Archipelago, 

 Feb. 22, 1908, 12 fathoms, sand). One colony at each place. 



The United States National Museum has also a colony received 

 from the University of the Philippines collected at Bantayan by Dr. 

 L. E. Griffin and Mr. L. D. Wharton. 



Fig. 89. — Polycitob 



ianthinus sluiter. 



ZOOID. X 18. 



