ZOOLOGY. 527 



Cylindrical Snails, out of contrast to the Sole and Cari- 

 nate Snails or the Bivalve Mollusca, 



Closely allied now to these cylindrimorphous Conchozoa 

 are all those Mollusca in whom the keel (carina) or sole 

 is wanting ; i. e. such snail or mussel-like animals, which 

 either cannot transport themselves at all, or effect this 

 by means of fins or podoidal appendages, in short all 

 that have been called Snails, having no sole, and all 

 supposed to be Mussels, but without a keel. 



Now, the Heteropoda or Pterotracheae and the Ptero- 

 poda or Clionae have projecting processes which act like 

 fins. 



The Brachiopoda or Terebratulae, though unendowed 

 with the power of locomotion, have, as their first name 

 implies, arm-like organs. 



The Cirripedia or Lepades, being likewise without the 

 power of continuous motion, possess podoidal or foot- 

 like appendages. In both these families, however, these 

 appendages are nevertheless true motor organs ; for by 

 means of them they seize their food, an act which 

 hitherto has been seen to take place neither in the Snails 

 nor Bivalve Mollusca. 



Lastly, the prehensile organs dwindle down into mere 

 filaments or small lobes, but the body always retains its 

 cylindrical form without keel and sole, as in the Ascidise 

 or Meerscheiden. 



In the Salpae only the cylindrical body is left, unto 

 which appendages are still, and not rarely either, attached, 

 serving them wherewith to lay hold of each other. In 

 accordance consequently with then- external form all these 

 animals appertain to one class along with the Cuttle- 

 fishes. I call them Kracken. 



The renal organs are still not to be found in all of 

 them; the structure alone of the heart agrees essen- 

 tially, despite of its simplicity, with that of the Cuttle- 

 fishes. In the Ascidiae, simple as well as compound 

 species, it is indeed but a single, though muscular 

 pouch. Now, this pouch drives the blood alternately, at 

 one time into the branchiae, at another backwards into 



