TUNIC AT A 



655 



D. kowalevskyi* (A. Agassiz) (Fig. 997). Length 15 cm. or more; 

 color of proboscis pinkish-yellow; collar same color but darker; body 

 orange yellow : Massachusetts Bay to Beaufort, N. C. ; often common 

 on clean sand flats. 



D. pusillus Ritter. Length 20 cm. or more; color orange: southern 

 California. 



2. Harrimania Ritter. Proboscis short, with 2 

 pores: 1 species. 



H. maciilosa Rit. Length 10 cm.; proboscis 13 

 mm., collar 4 mm., abdomen 89 mm. long; color dark 

 grayish-gi-een ; proboscis mottled: southern Califor- 

 nia; often common. 



Fig. 997 — Dolicho- 

 glossus koicalevskyi 

 (Shipley and Mac- 

 Bride). Explanations 

 as in Fig. 996. 



SuBPHYLUM 2. TUNICATA.f 

 (Urochordata.) 



Degenerate Cliordata in most of 

 which the body of the adult is more 

 or less cylindrical or globular in 

 shape and is encased in a character- 

 istic cutieular covering called the tunic (Fig. 998, 7). This tunic is 

 secreted by the underlying epidermal cells, but in most tunicates differs 

 from a typical cutieula in that it is composed largely of cellulose and 

 contains also mesenchyme cells, which have migrated into it, and also 

 blood spaces. Immediately beneath the tunic is a second very definite 

 structure called the mantle (11), which is a firm, composite tissue made 

 up of connective tissue fibers and enclosing muscles and blood vessels. 

 Very characteristic are the large pharynx, or branchial sac, and the 

 endostyle. The former (8) is the anterior portion of the digestive tract 

 and occupies the greater portion of the body. The mouth leads into it, 

 and through the openings in its walls the respiratory water streams 

 either directly to the outside, as in the Larvacea, or, as in the other 

 tunicates, into the large cloacal or peribranchial space (Fig. 999,10), 

 which communicates with the outside through the cloacal aperture. The 

 endostyle (6) is a glandular, ciliated groove which lies in the mid-ventral 



* See "The History of Balanoglossus and Tornaria," by A. Agassiz, Mem. Amer. 

 Acad. Arts and Scl., Vol. 9, p. 421, 1873. 



t See "Description of Some Imperfectly Known and New Ascadians from New 

 England," by A. E. Verrill, Am. Jour. Sci. and Arts, 3rd ser.. Vol. 1, 1871. "The 

 Invert, of Vineyard Sound," Rep. of U. S. Fish. Com., 1873. "A Revised Class, of 

 Tunicata," by W. A. Herdman, Jour. Linn. Soc. ZooL, Vol. 23, p. 558, 1891. 

 ' Tunicata," by O. Seellger and R. Hartmayer, Bronn's Klass. u. Ord. des Thierr., 

 1895-1911. "The Pelagic Tunicata of the San Diego Region, excepting the Larvacea," 

 by W. E. Ritter, U. of Cal. Pub. ZooL, Vol. 2, p. 51, 1905. "The Pelagic Tunicata," by 

 W. E. Ritter and E. S. Byxbee, Mem. Mus. Comp. Zool., Vol. 26, 1905. 



