A MANUAL jOF ZOOLOGY 



2. Vorticella 



Review the directions for the paramoecium and answer 

 the same questions in reference to the vorticella as far as 

 they apply. Note the difference in shape. It will be noticed 

 that this animal has a stalk and is regularly fastened to 

 some support. What is the structure of the stalk? Study 

 the peristome (rim of the body), the disk (within the peri- 

 stome), myophan iayer (striated base of body), and the 

 vestibule (entrance to the gullet). Mate a drawing on a 

 large scale showing all parts. From the movements what 

 would you consider the function of the stalk to be? Is the 

 body always in connection with the stalk? If not, there 

 must be some free swimming forms. In addition to the 

 methods of reproduction* in the paramoecium the vorticella 

 ha? another method that is called encystation. Look for 

 specimens of this type. Make a drawing representing all 

 the stages of reproduction. 



MULTICELLULAR ANIMALS 



PHYLUIVI PORIFERA 

 PORIFERA, (SPONGES) 

 1, Ascon Sponge 

 Leucosolenia. 



This is a marine form .found abundantly along the New 

 England shores fastened to seaweed, submerged wood, etc., 

 just below low tide mark. Note the difference in size of 

 the specimens submitted for, examination. Study- them 

 with the hand lens. Note, the cylindrical sponge body. Do 

 the two ends difCer? Note the opening at one ehd, the 

 osculum. Press the sponge lightly. Notice the flexibility 

 of the wall. Note the buds on the larger specimens. Do 

 the buds have oscula? Carefully cut a sponge from the 

 osculum to the base. Lay the cut specimen open in water 

 with the cloacal surface up. Does this chamber communi- 

 cate with that of the buds? 



Place one half of the specimen where it will dry, and 

 the other half in borax carmine, from one to several hours. 

 While the first specimen is drying draw a cluster of 

 sponges, illustrating all the points coifsidered up to this 

 time. Examine the cloacal surface of the dry specimen 



