1 8 Invertebrate Zoology. 



ectodermal, endodermal, and supporting layers? Does the 

 body-cavity extend into the tentacles? 



Illustrate the internal anatomy by diagram. 



The Digestive, Circulatory, Muscular, and Nervous 

 Systems are not essentially different from the same of the 

 Campanularian. 



The Reproductive System. As in the Campanularian, 

 reproduction may be asexual (branching and budding) or it 

 may be sexual. 



Though, as already noted, gonangia are not produced, 

 medusa-buds are abundantly found attached, as was the case 

 in the previously examined specimen, to the body or manu- 

 brium of the hydranths. An examination of medusa-buds 

 in varying stages of development will show that they arise 

 as simple outpushings, or evaginations, of the body-wall. 

 The more mature buds (about one-sixteenth of an inch in 

 diameter) have all the essential characters of the same of 

 the Campanularian, though the umbrella is here strongly 

 four-ribbed and considerably elongated. The chymiferous 

 tubes are four in number, and lead from the cavity of the 

 manubrium. The velum has but a small opening leading 

 into the cavity of the umbrella, and the marginal sense-organs 

 are visual (ocellate). Either eggs or spermatozoa are devel- 

 oped from the wall of the manubrium and are often in such 

 quantity as to distort the medusa. One or two of the eggs 

 are frequently much larger than the others, and may be 

 thrown off before the medusa-bud breaks away from the 

 hydranth. 



Make a drawing of a mature medusa-bud. 



