TUNICATA. 



103 



Family Octacjiemidce includes 0. hythius, a deep-sea Salpid, in which 

 the body forms a flattened disk produced into eight radiating lobes. 



Fis:. 22. 



Salpa runcinata-fiisiformis. A. Chain form. B. Solitary form. 1-9, muscle 



bands ; em, embryo ; m, mantle ; vise, visceral mass or nucleus. 



(Herdman : Tunicata, Encyclopsedia Britannica.) 



Fig. 23. 



irl 



>at.l 



h si 



Doliolum denticulatum, sexual generation, from the left side. 



m'-TO^ muscle bands ; at, atrial ; hr, branchial apertures ; hr s, branchial 



sac ; sg, stigmata ; st, stomach ; ng, nerve ganglion ; so, sense organs. 



(After Herdman, Encyclopsedia Britannica.) 



Family Doliolidm. The body is cask-shaped and surrounded by 

 circular hoops. The branchial and atrial orifices are at the opposite 



