450 University of California PxMications in Zoolocjy [Vol. 16 



Digestive system (pi. 41, fig. 29) . — On left side of animal. Storaacli, 

 in lower left half of body near ventral side-wall, possessing about 

 thirty close, regular, ridges or folds. Esophagus somewhat less than 

 half as long as stomach and joins latter at its posterior end. Long 

 axis of stomach parallel with that of body. Intestine, immediately 

 upon emerging- from the pylorus, bends posteriorly and lies along 

 upper half of stomach ; it makes U-shaped bend anteriorly to form the 

 rectal arm, which is about twice as long as the descending portion ; 

 anus with from six to sixteen blunt lobes. Inside the intestine, run- 

 ning its entire length, is a broad, fleshy fold that rolls up to form a 

 tube. At the pylorus this expands into a bulb cleft on its surface. 

 Running the entire length of the intestine is a clear, thin strip of wall 

 about opposite the fold. In the stomach near the dorsal side is a fold- 

 less strip, the width of several folds. A larger and broader fold than 

 the others borders this plain surface on one side. 



Reprnductive system (pi. 41, figs. 28, 29, and 31). — Ovaries much 

 elongated, cylindrical masses, two on each side of the body ; those on 

 the right longer, extending nearly entire length of the body; those on 

 the left considerably shorter. Of these latter the larger lies in the 

 loop of the intestine and follows the rectum. The smallest ovary 

 extends diagonally from the pyloric end of the stomach to end near 

 its partner. Ovarian cylinders narrow down to short necks or oviducts 

 near base of atrial siphon. Arranged along both sides of the elongated 

 ovaries are series of testicular lobes, whose ducts unite on the mid- 

 line of the inner surface of the ovary, and the common vas deferens 

 thus formed ends as a papilla, a little short of the termination of the 

 oviduct. The shape of the testicular lobes varies considerably, being 

 simple and club-shaped in the younger individuals, but becoming 

 bifurcate and irregijlarly branched in the larger ones. 



Breeding tinip. — The summer months at least, in Monterey Bay. 

 Ob.servations on the point have not been made at other times and in 

 other localities. 



Habitat and distribution. — The littoral zone from British Columbia 

 at the north to the southern limit of the United States at the south, 

 according to present knowledge. 



That this, one of the earliest known and most familiar ascidian 

 species of Pacific North America, should have remained to this time 

 without a detailed description is one of the vicissitudes in the progress 

 of knowledge of our local marine fauna. 



Although the specifications as to color in the diagnosis is the 

 simple.st statement that can be made, it would have to be much modi- 

 fied to make it apply to all individuals. Rarely if ever does it happen 

 that a grown specimen is uniformly colored. The anterior part and 

 one whole side of the animal are frequently more highly colored. 

 Occasional specimens are almost devoid of the red color. 



The flutings of the test are real structural differentiations and not 

 mere folds, the test being much thicker in the ridges than in the 



