SALPA REPRODUCTION 



103 



another, the aggregated form being usually more rounded, ovoid, 

 or fusiform (Fig. 61, A), and the solitary more quadrangular, 

 and often provided with conical processes or projecting points. 



The solitary form gives rise, by gemmation at the posterior 

 end of the endostyle (Fig. 63), to a complex tubular stolon, con- 



PiG. 63. — Diagram to 

 show the relations 

 of the groups of 

 young buds, -when 

 first formed on the 

 stolon of Salpa. at, 

 Atrial aperture ; Jr, 

 branchial aperture ; 

 el, elaeoblast ; end, 

 endostyle ; h, heart ; 

 n.g, nerve - gang- 

 lion ; ov, ovum ; s, stolon ; st, stomach ; I, II, III, groups of buds. (After Brooks.) 



taining processes from the more important organs of the parent- 

 body, which give rise to an endodermal tube, two peribranchial 

 tubes, a neural tube, two blood-sinuses and mesoblast cells, a 

 genital cord, and over all the ectodermal covering (see Fig. 64). 

 This stolon becomes segmented (Fig. 63) into a series of buds or 



Fig. 64. — Transverse 

 section through 

 endostyle and 

 young stolon of 

 Halpaipinnata. ec, 

 Ectoderm of parent 

 reiiected at ec' to 

 cover base of 

 stolon ; ec" , ecto- 

 derm of stolon ; 

 end, endoderm of 

 stolon ; g, ovary ; 

 mes, mesoderm 

 cells ; n, nerve- 

 tube of stolon ; 

 p,hr, peribranchial 

 tubes of stolon. 

 (After Brooks.) 



mes. 



young " chain " individuals, of which there may be several 

 hundreds. As the stolon elongates (Fig. 61, B, st"), the buds 



