242 



BY THE DEEP SEA. 



annexed diagram. In the figure the reference letters are of 

 the following signification : # , branchial apertures ; , atrial 

 apertures ; c, young individuals arising from the runners s. 



From this form it is an easy transition to the Ascidians 

 known as Salpce. These have the branchial aperture (b) at 



one end, and the atrial 

 opening (a) at the other. 

 In the figure the heart 

 is shown at e, and the 

 branchial chamber at d. 

 These Salpce are both 

 solitary and compound 

 Ascidians, for it is a 

 singular fact that the solitary form as here shown produces 

 buds which develop into a connected series or chain of indi- 

 viduals. These, in turn, instead of reproducing the species, 

 in a similar manner produce eggs, each of which gives rise to 

 a solitary individual. In our figure of Salpa maxima, the 

 letters c indicate the points of attachment of the Salpa colony ; 

 and the next figure represents a portion of the Salpa-chain. 



SALPA MAXIMA. 



PART OF A CHAIN OF SALPJ3. 



Frequently, in gazing down the sides of a still, deep rock- 

 pool, we shall observe a coating of dark-grey jelly, in patches 

 as big as one's hand, and on carefully taking off an inch or 

 two of this, and examining it with the lens, or a low power of 

 the microscope, we shall observe a number of elegantly-formed 

 jars to be set in the jelly, and as we look their mouths and 

 necks are raised above the surface of the jelly and opened. 



