SOME PUGET SOUND ASCIDIANS. 593 



about three between them, this number varying from one to five 

 according to the size of the individual ; folds ending abruptly at 

 the oesophageal opening where the bars are prolonged in the 

 form of languets ; transverse vessels of at least three sizes, usually 

 six narrow ones between two broad ones. Meshes oblong, 

 crossed by dehcate secondary vessels. Stigmata six to twelve 

 in a mesh, small and narrow ; a longitudinal vessel often running 

 part way down the branchial sac and so forming smaller, square 

 meshes (PI. XIX., Fig. 22). 



Tentacles : About twenty-four in number, twelve large, very 

 stout ones, twice branched, and as many small ones alternating 

 with them (PI. XIX., Fig. 23). 



Peritubercular area shallow ; dorsal tubercle large ; mouth of 

 hypophysis with its horns turned in and twice coiled. 



Dorsal Lamina composed of languets, short at the anterior 

 end and passing part way round the opening of the oesophagus. 

 No basal membrane present ; transverse vessels on the right 

 side ending in languets opposite the dorsal languets, and in the 

 larger specimens, a few small accessory languets present between 

 these two rows (PI. XIX., Fig. 23). 



Endostyle veiy broad. 



Intestine : Making a wide loop ; oesophageal opening about 

 half way between the anterior and posterior extremities of the 

 branchial sac ; liver large. 



Ovaries : One on each side of the branchial sac, in the form 

 of a slender tube bent like the letter S lying down. The genital 

 duct directed upward ; endocarps present on the mantle. 



There are two specimens of this species in the collection, 

 both small and apparently young. One measures 2.6 x i cm., 

 the other 5 x 2.3 cm. The color of the test seems to be well 

 preserved. The above description is based partly on these two 

 specimens and partly on a number from the Young Naturalists' 

 Society of Seattle. The latter are preserved in alcohol and 

 their test is colorless. It is also thicker and lacks the semi- 

 transparency characteristic of the test of the Columbia specimens. 

 The largest one in the Young Naturalists' collection measures 

 5x2 cm. and the genital organs are perfectly developed. 



