SEA-SQUIRTS. 149 
Appendiculariz.—These (Fig. 188) are the simplest 
forms of the class, minute pelagic creatures with tadpole- 
like tails. 
Fic. 188.—Afpendicularia flabellum, 1. The entire animal, with the 
“tail” in its ordinary position, or turned forward. II. Side view of the 
body, with the ‘‘tail” forcibly bent backward. 4, the body; 2, the 
tail; ¢, oral aperture ; 4, the pharynx; c, an atrial opening; d@, the cor- 
responding stigma, with its cilia; 4 rectum; g, cesophagus ; %, 2, stom- 
ach ; /, urochord; m, cellular patch at the side of the oral end of the 
body ; 4, ganglion; g, ciliated sac; 7, ear; s, posterior nerve with its 
ganglia, ¢; ex, endoderm ; ec, ectoderm. (After Huxley.) 
Works on Tunicates for further reference. 
“ Ascidians of the Coast of New England,” A. E. Verrill, in “ Ameri- 
can Journal of Science,” vol. i, 1871 ; ‘Structure and Affinities of the 
Sea-Squirts (Tunicata),” J. C. Galton, “ Popular Science Review,” July, 
1868 ; “Invertebrata of Vineyard Sound,” Verrill ; “ Development 
of Salpa,” Brooks, “ Bulletin of Comparative Zodlogy,” Cambridge, 
1876. 
