642 A Remarkable Life History and its Meaning. [November, 
tropics than in more northerly or southerly latitudes, the former 
seas are more 
favorable than the latter to the development of 
these animals, which multiply with astonishing rapidity when 
furnished with abundant food. As they feed upon the microscopic 
Fig. 43. 
a, test; b, outer tunic; d, wall of atrial chamber ; e, branchial aperture 
girdles ; g, atrial aperture ; A, breathing chamber ; 7, 
geal fold ; 
w, languette 
il ` 
= 
z3 
I 
E7 a 
aiaa 
\ 
EA 
Taar, 
. . m i ‘3 e above : 
Side view of an adult solitary Salpa, with the hæmal snr soe 
ture r: i, atrial chamber ; l, arth 
m, endostyle; n, gill; o, mouth; r, heart; u, chain of males; Y, gang’ 
(= Soe aera ee aia eer a 
