SALPA, AMPHIOXUS 243 



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 peripharyngeal 

 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 

 homologous 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, nonsexual Salpa. 



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

 seen attached by "placentae" 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 laterodorsal view is best). 



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



1893. 

 Grobben: Doliolum und sein Generationswechsel. Arb. Zool. Inst. 



Wien, 4, 1882. 

 Metcalf: The Salpidse: A Taxonomic Study. Bull. U. S. Nat. Mus., 



100, 1918. 



CEPHALOCHORDA 



AMPHIOXUS LANCEOLATUS 



While living material is not easily provided for labora- 

 tory work, it should be understood that this form spends 

 most of its time in the sand in rather shallow water and that 

 it burrows with great ease by movements of the body. 



1. In an alcoholic specimen note the dorsal, ventral, and 

 caudal regions, and also the median fin, metapleural folds, 

 muscle plates or myotomes, buccal cavity fringed with cirri, 

 atriopore, and anus. 



2. Using a specimen that has been macerated in 20 per 

 cent nitric acid, remove the skin and myotomes from the 



