REPORT ON THE TUNICATA. 311 



Fig. 7. The anterior end of an ascidiozooid of Botryllus 

 smaragdus, showing the arrangement of the 

 tentacles, &c., magnified 300 diameters. 



a, anus ; at, atrial aperture ; br, branchial aperture ; 

 br.f, fold in branchial sac ; en, endostyle ; e.gr, epibranchial 

 groove ; d.l, dorsal lamina ; d.t, dorsal tubercle ; gl.d, duct 

 of neural gland ; i, intestine ; i.l, internal longitudinal bar ; 

 I, dorsal languet ; Lv, fine longitudinal vessel ; m.f, muscle 

 fibres ; oe, oesophagus ; pig, mass of pigment cells ; 

 p.p, peripharyngeal band ; p. ah, post-abdomen ; r, rectum ; 

 sg, stigmata of branchial sac ; st, stomach ; sph. sphincter ; 

 tri, tentacles ; tr, transverse vessels. 



