MUSEUM OF COMPARATIVE ZOOLOGY. 



307 



S;ilpa chain is discharged from the body of the solitary form each 

 " zooid " * contains a single egg,t which is situated upon or very near 

 the median plane of the neural side of the animal, within the sinus 



Fig. 8. 



Fig. 10 



Fig. 8, egg before impregnation. Figs. 9 and 10, egg during impregnation. Figs. 11 and 12, 

 changes following impregnation : 6, outer tunic of male ; c, wall of branchial sac of male ; 

 h, cavity of branchial sac of male ; 1, sinus system of male ; 2, blood corpuscles of male ; 

 3 gubernaculum ; 4, yolk ; 5, germinative vesicle ; 6, spermatic filaments ; 7, capsule of egg ; 

 8, nucleus. 



system, and midway between the atrial orifice and the stomach (see 

 P'igs. 31, 32, 33, and 34, s). There is no observable trace of a vitel- 

 line membrane ; the yolk is transparent without granules, and the 

 germinative vesicle does not contain a germinative dot (see Fig. 8). J 



* The use of the word "zooid" in this connection must not be understood to imply- 

 any opinion as to what is or is not a zoological individual; it is used merely as a con- 

 venient word to designate one of the males which compose a chain. 



t Leuekart says (Ueber Salpen, p. 49) that some species contain more than one egg. 



J Huxley, who studied what appears, from his description, to be the species here 

 described, says (Salpa and Pyrosoma, p. 577) that there is a germinative dot occasion- 

 ally. Leuekart (p. 51) gives the germinative dot as one of the characteristics of the 

 egg, but I have not been able to find it in any instance. 



