15 



HYDROZOA 



HYDROZOA. 



HYDROMEDUS^E. 



i. Colony of Obelia (as type of Calyptoblastic Hydroid). Ccenosarc; perisarc; hydrotheca; gono- 

 theca; blastostyle; medusa-bud. The material of Obelia and other hydroids is given to the student 

 preserved in 70 p.c. alcohol. It should be stained in borax carmine (in 50 p.c. alcohol), dehydrated 

 and mounted in Canada balsam. 



2. Medusa of Obelia (type of Leptomedusse). Tentacles of edge of umbrella ; manubrium ; the 

 four gonads ; the four radial canals ; the eight otocysts. 



