NO. 1989. A8CIDIAN8 FROM NORTHEASTERN PACIFIC— RITTER. 497 



This species belongs to the mentula section of the genus, that is, 

 the section with the branchial sac extending well behind the intesti- 

 nal viscera, and seemingly surpasses all other species in the length 

 of the posterior pouch. So far as concerns size and proportions of 

 the animal as a whole, it appears to resemble Ascidia elongata Roule 

 more than any other species. However, in internal structure it 

 appears to differ quite sharply from that species. Although the 

 description of elongata (Roule, 1884) is not full enough to enable me 

 to make comparison complete at every point, it is sufficient to war- 

 rant the inference that vermiformis differs from elongata in the greater 

 relative length of the postvisceral sac pouch, in the greater number 

 of tentacles, and in the absence of intermediate papillse on the internal 

 longitudinal vessels; also the intestinal mass of 'vermi/bfrnis seems 

 to be more compact and more elongate, proportionally, than that of 

 elongata. These inferences are drawn from Roule's statements con- 

 cerning the similarities and differences between elongata and mentula. 



Type-locality.— Albatross 2945, lat. 34° N.; long. 119° 29' 30'' W., 

 off southern California, 30 fathoms, pebbly bottom, February 6, 1889; 

 4 specimens. 



Type.— Cat. No. 5792, U.S.N.M. 



Worth noting is the fact that two crustaceans were found m the 

 branchial sac of one of the specimens. These have been kindly 

 identified by Miss Mary J. Rathbun of the United States National 

 Museum. One was Pontonia calif orniensis, a shrimp; the other 

 Cryptophrys concharum, a crab. 



PHALLUSIA UNALASKENSIS. new species. 

 Plate 36, figs. 43-45. 



Superficial characters. — ^Very soft and mobile to handling; elongate, 

 subcylindric, length 6 cm. major, transverse diameter 2.5 cm. Firmly 

 attached at posterior end to sand-encased worm tubes. Branchial 

 orifice anterior, atrial distant from branchial about the diameter of 

 the branchial siphon; both orifices 6-lobed, the lobes not conspicuous 

 on surface, but clearly marked by radiating ridges on inner surface 

 of test; orifices situated on summits of firm rounded mound-like 

 siphons, the branchial larger (pi. 36, fig. 43). Test thin and trans- 

 parent throughout except in the siphonal mounds. Mantle very thin 

 and almost as transparent as glass excepting for the small scattered 

 muscle fibers contained in it on the right side of the body and around 

 the orifices; the abrupt thickeniag at the branchial orifice in the 

 above-mentioned mound-like siphon forming a conspicuous object on 

 the animal removed from the test. 



Respiratory system. — Branchial tentacles about 24, of several sizes, 



but all very small in proportion to the size of the animal, situated 



on a low ridge running concentric with the peribranchial band, from 



which it is removed about one third the distance between the peri- 



80459°— Proc.N.M.vol.4r)— JC 32 



