PACIFIC TUNICATA OF U.S. NATIONAL MUSEUM 211 



In branchial sac 8 or 9 plications on left and 8 to 10 on right side, 

 ventralmost fold usually rudimentary on each side, although well 

 defined in anterior portion of branchial sac. Inner longitudinal 

 vessels arranged (D = dorsal, V= ventral): 



13 mm. long specimen (USNM 11525) 

 Left D 1 (14) 1 (12) 1 (16) 1 (14) 1 (13) 2 (11) 

 Right D (13) 1 (12) 1 (16) 2 (13) 2 (13) 2 (13) 



28 mm. long specimen (USNM 11704) 

 Left D 2 (20) 2 (19) 2 (20) 3 (20) 4 (18) 4 (15) 4 (13) 

 Right D 2 (17) 2 (18) 2 (21) 3 (21) 3 (18) 4 (20) 2 (17) 



30 mm. long specimen (USNM 11704) 

 Left D 1 (21) 2 (20) 2 (21) 4 (21) 3 (19) 3 (18) 2 (15) 

 Right D 1 (16) 2 (18) 2 (22) 3 (19) 3 (18) 3 (19) 3 (16) 



35 mm. long specimen (USNM 11523) 

 Left D 2 (21) 2 (19) 3 (21) 3 (20) 4 (19) 4 (18) 3 (15) 2 (11) 1 (3) V 



Right D 1 (20) 3 (18) 3 (23) 3 (21) 3 (22) 3 (20) 4 (18) 2 (14) 2 (11) (3) 1 V 



40 mm. long specimen (USNM 11524) 

 Left D 2 (20) 3 (19) 3 (22) 4 (19) 3 (19) 4 (18) 2 (17) 3 (11) 1 V 



Right D 1 (19) 2 (17) 3 (19) 3 (22) 3 (21) 3 (19) 3 (17) 2 (13) 1 (9) 1 V 



Arrangement of transverse vessels varies from: 1p3p2p3p1 

 (13 mm. long specimen) to 1 4 3 4 2 4 3 4 1, 1 333 2 333 1 or 1 444 3 444 

 2 444 3 444 1, excluding paras tigmatic vessels (numerals indicate order 

 of thickness of vessels, p represents parastigmatic vessel). Parastig- 

 matic vessels found most commonly in posterior portion of branchial 

 sac. Elliptical stigmata 5 to 8 in each mesh. Tentacles 21 (13 mm. 

 long individual) to 35 (25 mm. long individual), arranged partly in 

 order: large small medium small large; also minute ones found at 

 some intervals ; branches in 4 to 5 orders, very complicated. Ciliated 

 groove rouglily U-shaped with both horns strongly in curled; frequently 

 slightly inclined towards right side as seen from front. 



Second intestinal loop very deep, axis passes through approximately 

 middle of ventral branch of first intestinal loop. From 2 to 6 endo- 

 carps on intestinal wall just posterior to hepatic region. Liver pale 

 reddish brown in preserved specimens; minute finger-shaped papillae 

 on each hepatic lobule. Anal margin mostly plain, though rarely un- 

 dulating and forming several indistinct lobules. I^ft gonad consists 

 of 3 to 4 genital capsules (and several small ones in rare cases), right 

 consists of 2 to 5 capsules. Ovary occupies free surface of gonad and 

 testis is spread along attachment surface. 



Specimens itiom Saipan, the Gilbert Islands, and Port Jack- 

 son. — Specimens from Saipan 8-16 nun. m length, those from the 

 Gilbert Islands 16-17 mm., and the Au.stralian specimen 17 nnn. long. 

 Attached to substratum by ventral side, sliglitly inclined to left or right 

 side, or by left side of body. Both siphons rather short, branchial ter- 

 minal or subterminal, atrial located in most specimens slightly pos- 

 terior to middle of body. Test leathery, thin, varies from yellowish 



