184 CHOBDATA. 



2. The oral aperture is dorsal and far forward. Are there 

 any muscles for opening and closing it? 



3. What is the form and position of the cloacal aperture? 

 Is it provided with muscles? 



4. Observe the processes of the tunic, one anterior, one mid- 

 ventral, and two posterior. These processes (except the dorsal 

 posterior) serve to unite the individuals of the chain. 



5. Does the animal show perfect bilateral symmetry? 



6. Posterior to the mouth, the ganglion and the pigmented 

 eye-spot may be found. Immediately anterior to these is the 

 elongate hypophysis. 



7. Note the endostyle in the floor of the pharynx, and the 

 dorsal lamina between the pharynx and atrial cavity. From the 

 anterior end of the dorsal lamina the peri-pharyngeal bands 

 extend to the anterior end of the endostyle. 



8. The pharynx communicates laterally with the atrium by 

 means of two very large stigmata. These are probably homol- 

 ogous with the numerous stigmata of Molgula. 



* 9. The "nucleus," the large mass in the posterior end of the 

 body, contains the stomach and intestine. 



The ova are fertilized by spermatozoa from individuals of 

 another chain, since in the same chain the spermatozoa 

 mature much later than the ova. The fertilized ova migrate to 

 a spot in the right wall of the atrium, where they develop into 

 the solitary non-sexual Salpa. 



In this species as many as three or four embryos may be seen 

 attached by "placentce" to the cloacal wall on the right side. 

 The placental connection finally separates, and the embryo 

 passes out through the cloacal aperture. 



Make an enlarged drawing (a latero-dorsal view is best). 



Brooks: The Genus Salpa. Mem. Biol. Lab. Johns Hopkins Univ., 2, 1893. 

 Grobben: Doliolum und sein Generationwecksel. Arb. Zool. Inst. Wien., 4, 



1882. 



