PEROPHORA, BOTRYLLUS 239 



4. Study buds of various sizes and see how the inner ves- 

 icles arise from the epicardiac tube. 



5. Try to make out the entire course of the circulation of 

 the blood. Notice especially the heart, branchial vessels, 

 vessels of the mantle, and the circulation of the stolon. 

 Watch the pulsations of the heart and see the reversal of the 

 blood current. Is the heart beat synchronous in different 

 individuals? What part of the blood is colored? 



6. Study the action of the cilia in the gill clefts. 

 Drawings of a colony and of an individual are desirable. 



Lefevre: Budding in Perophora. Jour. Morph., 14, 1898. 



BOTRYLLUS 



The small, radially arranged colonies of this composite 

 ascidian are common on eel grass, from which they may be 

 separated by means of a knife, and studied alive in a watch 

 glass with a lower power of the microscope. The cleaner and 

 more transparent colonies should be selected. 



1. Note the character which makes the form a "compo- 

 site" ascidian — the common tunic or test. Find the mouths 

 and the common cloacal cavity. Would it be correct to say 

 that a common atrium is present? 



2. Find the annular blood vessel and its numerous am- 

 pullae. Do you observe any striking facts regarding the cir- 

 culation? What functions have the ampullae? 



3. With your knowledge of Molgula as a guide, identify 

 as many of the organs as possible. (This is sometimes diffi- 

 cult because of pigment.) 



4. Very young colonies, with only the first one or two 

 generations of buds, may also be found on eel grass, appear- 

 ing as transparent hemispherical lumps about a millimeter in 

 diameter. These should be fixed and stained on the eel grass, 

 and later mounted (either still attached or removed) in bal- 

 sam. These will show very clearly the formation of buds of 

 the "parietal" or "peribranchial" type. (In this type the 

 outer vesicle arises from the integument, and the inner vesicle 



