-41- 



Lettering. 



a.h.l. anterior horizontal l.v. lateral invagination. 



lamella. 1. loop of the ciliated 

 aort. aorta. groove. 



art. pseudobranchial artery, l.o.g. lateral celD -group, 



b.g. basilar (salivari) gland. l.c.h. lateral ciliated cham- 

 b.m. basilar muscle, bars, 



br. point of separation of oili- i". membrane over o. 



ated and of cover cells, m,o,g,, m,©,^*., etc, median 

 b,w. body 'wall, cell-groups, 



c.b. cartilaginous bars. m,o,h. median ciliated oham- 

 cd.r, ciliated dorsal ridge, ber. 



ch, notochord. mes, mesoblast, 



c. t. connective tissue envel- m.l. median lamella. 



ope. S«l** extreme posterior end 



d. duct of basilar gland. of median lamella, 



d,c,g, dorsal ciliated groove. n.fl. nuclei of ciliated cells, 



d,l, cover cells (Decklamelle) . rugl. nuolel of gland cells, 



e, eye, o. si it -like opening of cell- 

 f.l. ciliatel cells, groups. 



g.l. gland cells (r)ru8enlamel- oes. oesophagus. 



le), P* side pouch of ventral cili- 

 g,p, gill pouch. ated groove, 



gr, primary group of gland cells, phar, pharynx, 



gr', secondary group of gland p.h.l, posterior horizontal 



cells, lamella. 



