106 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



Mantle moderately thick; its muscles are not gathered into con- 

 spicuous hands. 



Tentacles apparently normally 16, of two sizes placed alternately. 

 At their bases an annular membrane extending around the whole 

 circle unites them all together. Atrial tentacles are present, but are 

 so minute and slender as to easily escape notice. They are arranged 

 in a large circle. Peculiar thread-like appendages of the inner wall 

 of the mantle in the atrial region have been described by Sluiter 

 (1914) in this species, and are present in the Philippine specimens 

 also. 



Dorsal tubercle elliptical, with the long diameter placed longitu- 

 dinally; its orifice of similar outline, also with its long diameter 

 longitudinal. 



Dorsal lamina plain-edged. 



Branchial sac with four distinct folds on each side and numerous 

 internal longitudinal vessels. Their distribution in a large zooid 

 was found about as follows : 



Right side: dorsal 2 (14) 4 (S) 4 (13) 3 (6) 2 ventral. 

 Left side: dorsal 2 (13) 4 (9) 3 (12) 4 (7) 2 ventral. 



Transverse vessels of nearly uniform size. Only 2 to 3 stigmata 

 generally intervene between internal longitudinal vessels on the inter- 

 vals between folds, but a larger number occur between the endostyle 

 and last vessel, and 8 or 10 stigmata are often present between the 

 median dorsal vessel and the first internal longitudinal vessel, espe- 

 cially on the right side of the body. Stigmata oblong or elliptical, 

 often rather wide. 



Esophagus short and curved; stomach short with few (about 19) 

 longitudinal folds and a small curved pyloric caecum. Intestine 

 large, running forward from the stomach, then bending back along 

 its side. The rectum is only moderately long, and begins with a 

 sharp forward bend of the intestine. Its orifice is two-lipped. 



Gonads rounded or oval sacs, each normally containing a consider- 

 able number of eggs and two large oval or sausage-shaped testes. 

 These gonads may number a dozen or more on each side of the body 

 and are placed in an irregular row each side of the mid-ventral line, 

 attached to the inner surface of the mantle. 



The larger of the two colonies (No. 124), (Cat. No. 5977, 

 U.S.N.M.), is from station D5557 (near Cabalian Point, Jolo Island, 

 13 fathoms, sand and coral. September 18, 1909). The other (No. 

 137) (Cat. No. 5976, U.S.N.M.), nearly as large, is also from Jolo 

 Island, February 11, 1908. The Philippine specimens have the 

 longitudinal vessels more numerous and have somewhat smaller 

 zooids than Sluiter's type, which was from Sarassa Island, 36 meters. 

 The writer has in no case found more than two testes in a gonad 





