1876.] A Remarkable Life History and its Meaning. 645 
ee eee EY 
cae 
of the heart. This was discovered in 1824 by Van Hasselt, and 
although it is not peculiar to Salpa, but is shared by all the Tuni- 
Ti 
ve 
is 
A 
(usri O f 
l K 
Me, 45. Side view of adult chain-salpa, figured ith, Ge eee niet 
: ‘Most: a, test; b, outer tunic ; d, atrial tunic; 2, branchial aperture ; T , muse ne 
branchial aperture; f/’, muscles of atrial aperture; 9, ee ty. r v ob 
— i l, epipharyngeal fold; m, endostyle ; n, gill; r, heart; s, embryo; t, € 
i ` w, languette. , 
“tacan be best studied in this genus, owing to its ARES 
= 7. The body of the animal is 50 perfectly transparent that 
