C. PREPARED SECTIONS. 



Study prepared sections of the arm of a starfish and observe : 



1. The hepatic caeca. How are they supported? What is their 

 structure ? 



2. The radial canal, connecting tubes, tube feet and ampullae. 



3. The thickened, deeply staining nerve, between the tube feet 

 and below the radial water tube. 



4. The perihaemal canal, divided by a thin partition, and lying 

 between the radial water tube and the radial nerve. 



Make a drawing of a section of an arm which will show these 

 points. 



D. PHYSIOLOGY. 



a. Observe a living specimen in the Vivarium and Note : ( i ) 

 Method of Movement. (2) Method of Feeding. How does it open 

 an oyster? How does it swallow the oyster? 



b. Place a starfish in a dish of sea water and observe its reactions 

 to the following stimuli : 



( i ) Mechanical; touch the end of an arm with your pencil and 

 note the response. 



(2) Gravity; place the animal on its aboral surface and observe 

 how it rights itself. 



(3 ) Place the animal so that bright sunlight falls on the tip of an 

 arm and note the response. 



RANA SP. (The Frog). 

 A. GENERAL STRUCTURE. 

 I. EXTERNAL CHARACTERS. 



Note the smooth moist skin over the entire animal ; the absence 

 of exoskeleton ; the head, trunk, two pairs of limbs ; the ab- 

 sence of a tail and of a neck. 

 a The head. Observe : 



1. The eyes are prominent and have lids; the ears are covered 

 over by a modified part of the skin, membrana tympani, posterior to 

 the eyes; the two anterior nares, or nostrils; the position of the 

 mouth opening; the soft flexible throat and hard parts of the 

 endoskeleton felt on the dorsal side of the head. 



2. Pass a bristle far into the anterior nares and one into the 

 ear through a hole cut in the membrana tynipani; on opening the 

 mouth the bristles will indicate its communications with the nostrils 



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