PACIFIC TUNICATA OF U.S. NATIONAL MUSEUM 49 



small protuberjvnces. About 20 tentacles, larger and smaller ones 

 diilerentiated, also some minute ones. Ciliated groove a small oval 

 opening. Stigmatal rows 11 on left and 12 o]i right side in the colo- 

 nies respectively, 10 mm. X 7 mm. and 8 mm, X 4 mm. m extent, but 

 8-10 rows in zooids from other cokjnies; 18 to 25 stigmata in each 

 row. Many papillae along edge of liorizontal membranes; approxi- 

 mately 1 papilla at each 1 or liy^ stigmata. Dorsal languets displaced 

 from the dorsomedian line to left side for distance of about 2 stig- 

 mata. Anus bilobed and opening at level of sixth transverse vessel. 

 Incubatory pouch at the level of the seventh stigmatal row; usually 

 2 embryos and 2 mature eggs found in pouches of zooids examined. 

 Ovary usually occupying the center of the testis or situated anteriorly 

 to it when postabdomen contains only a few testicular follicles ; testic- 

 ular follicles up to 19 in zooids examined, but as few as 6 in some 

 zooids of the colony 17 mni. X 5 mm, in extent. Pericardium less than 

 a third of postabdomen in length. 



A single embryo was found during dissection, oval in shape and 

 450/A in length. Three disc-shaped attachment processes are arranged 

 lineally, with elongated outline on the surface. Four pairs of ampul- 

 lae are distinctly formed. Two pigment flecks of the sensory organ 

 are obliquely arranged (fig, 14^). 



Remarks. — In addition to the above-described specimens, a small 

 colony, 6.5 mm. X5 mm, in extent and 2.5 mm. in thickness (USNM 

 11658) , was found attached to a piece of alcyonarian in a sample of the 

 benthonic organisms collected at Baliwasan, Philippines. The sur- 

 face of colony is thickly encrusted v/ith sand grains, although the test 

 itself is soft, gelatinous and not impregnated with sand grains. 

 Thorax about 2 mm. in length, abdomen two-thirds to three-fourths 

 the length of thorax. Postabdomen slightly longer than half of 

 abdomen. Branchial aperture 6-lobed. Tip of atrial languet with 

 several fuie protuberances as shown in fig, 1-li, A small but distinct 

 protuberance on dorsomedian Ime just posterior to atrial aperture. 

 About 10 longitudinal muscles on each side of thorax. Stigmatal 

 rows 9, up to 25 stigmata m each row. Papillae present on horizontal 

 membranes. About 20 very slender tentacles; ciliated groove an oval 

 orifice. Anus attached at level of fourth transverse vessel, but extend- 

 ing slightly anterior from this level. Ovary central (?), testicular 

 follicles as many as 50. Pericardium about one-fourtli tlie length of 

 postabdomen. This specimen differs from the typical P. tsutsuii by 

 having fewer stigmatal rows, the anus is situated more anterior and 

 the postabdomen contains many more testicular follicles. These 

 features are, however, hardly regarded as being of specific significance ; 

 probably the present specimen represents an extremity of intraspecific 

 variation. 



