112 



BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



Iii the only well-preserved specimen in the collection the colony is 

 thin and expanded, surrounding a piece of branching coral for a 

 length of about 40 mm. The coral polyps protrude through open- 

 ings piercing the colony, which does not appear to exceed 3 mm. in 

 thickness at any point. Test translucent and pale purplish in color ; 

 the zooids, which are arranged in complex branching systems, are 

 darker purple. 



Zooids rather elongate, attaining a length of about 2 mm. to 2.5 

 mm. when moderately contracted. Branchial aperture with 6 bifid 

 lobes. Atrial aperture large and commonly produced into a short 

 tube of large diameter, the anterior margin of which is often extended 

 to form a languet of considerable length, but 

 there is great individual variation in this respect. 

 Eight tentacles (four large and four small, 

 placed alternately) are readily distinguishable; 

 the existence of additional third order tentacles 

 is probable. 



Branchial sac long, with 15 to 16 rows of stig- 

 mata in some zooids, in others somewhat fewer; 

 about 23 stigmata in a row on each side. Three 

 internal longitudinal vessels on each side, spaced 

 apart about the width of five stigmata. Eight or 

 nine stigmata, however, intervene between the 

 last internal longitudinal vessel and the endo- 

 style. 



Stomach with about 10 or 11 rather narrow 

 longitudinal folds and a small caecum. (No 

 caecum is mentioned or figured by Herdman, 1886.) Anus slightly 

 2-cleft. 



Testes few in the zooids examined. Some of the zooids contain a 

 single large egg on one or both sides of the body anterior to the testes. 

 The well-preserved colony (No. 127) (Cat, No. 6031, U.S.N.M.) 

 mentioned above is from station D5144 (off Jolo Light, Feb. 7, 1908, 

 19 fathoms, coral sand). A small, poorly preserved specimen (No. 

 67) (Cat. No. 5907, U.S.N.M.), apparently of the same species, is 

 from station D5146 (near Sulade Island, Sulu Archipelago, Feb. 16, 

 1908, 24 fathoms, coral sand and shells). 



The type of this species was obtained by the Challenger Expedition 

 in latitude 11° 37' N. ; longitude 123° 31' E., 18 fathoms. Gottschaldt 

 (1898) records a small colony from Ternate, and the Siboga Expedi- 

 tion (see Sluiter, 1904, p. 101) obtained it at several other localities 

 on reefs in the Malay region. 



Fig. 67. — B otbyl- 

 ioides tyreum 

 Herdjian. Zooid. 

 X 20. 



