102 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



matter. Height of largest specimen from place of attachment to 

 branchial orifice, 45 mm.; greatest diameter at right angles to the 

 above., 33 mm.; lateral diameter (estimated), 12 mm. or less. 



Mantle dark colored, its muscles composed chiefly of separate fibers 

 or small irregular groups of fibers, the deeper and best-developed 

 layer consisting of those radiating from the bases of the siphons or 

 having a similar direction, the less complete superficial muscles cross- 

 ing them at right angles or obliquely. 



Tentacles few : 12 to 16 large ones probably represent two orders, 

 but are not very regularly arranged. Additional smaller ones occur 

 in only a few of the intervals. 



Dorsal tubercle large but not prominent; its orifice C-shaped with 

 the open interval forward ; horns not inrolled or incurved. 



Dorsal lamina plain-edged, broader in the posterior part. 



Branchial sac with four well-developed folds on each side separated 

 by rather wide intervals. Transverse vessels of four, in some places 





53 V_^_/- 54 



Figs. 53-55. — Pandocia ovata (Pizon). 53, Left and right sides of body. X .65. 

 54, Dorsal tubercle. X 8. 55, Gonad. Side next to branchial sac. X 25. 



five, orders quite regularly arranged, the smallest generally crossing 

 the stigmata.. Internal longitudinal vessels stout; their distribution 

 in the largest specimen is about as follows: 



Right side: dorsal 4 (11) 5 (14) 6 (19) 5 (14) 4 ventral. 

 Left side: dorsal 4 (10) 5 (15) 5 (IS) 5 (13) 4 ventral. 



They are rather irregularly spaced; in general there are 8 or 10, 

 sometimes 12, stigmata between them on the intervals between folds, 

 but along the median dorsal vessel and endostyde 15 or more. 



Intestine of large diameter but forming a rather compact rounded 

 loop within which a very large endocarp is situated. Stomach short 

 and rounded, without conspicuous plications and with a poorly de- 

 veloped pyloric caecum. Rectum abruptly bent forward; rather 

 short; margin of anus with only very rudimentary yet numerous 

 lobes. 



Gonads of the typical Pandocia type. Each a very small oval or 

 rounded sac with a very short neck, containing a central mass of eggs 

 bordered by a varying but not very large number of pyriform male 

 glands whose ducts converge on the unattached side of the gonad 

 toward the base of a papilla situated beside the neck of the gonad. 

 They unite and discharge by a common orifice at the summit of this 



