No. 6.] 



PHORONIS PACIFIC A. 



more closely related to the American than to the Australian 

 species. In size it resembles P. Bnskii, as well as in the com- 

 plexity of the lophophore ; though instead of three coils in the 



FIG. j. Diagrammatic cross-sections of the lopliophores of P. australis or P. Buskii (A), 



P. pacifica (5). 



c 



FIG. 2. Section through the upper third of P. pacifica; but one quadrant detailed ; semi-diagram- 

 matic, b, basement membrane ; c, circular muscle ; ec, ectoderm ; /, longitudinal muscle s ; 

 in, in', mesenteries; 7', median vessel ; , nerve ; o, oesophagus; r, rectum. 



