HYDROZOA 



123 



like network over a surface and develops at intervals 

 projecting points on which the zooids live. Each 

 colony consists of feeding members, of reproductive 

 members, and of a third kind which seems to have 

 a protective function. These last are more slender 

 than the others, and are without tentacles, but are 

 armed with lasso- or stinging-cells. The colonies are 

 of different sexes, the male being lighter in color than 

 the female colonies. The eggs develop into planulae, 

 which swim about for a while and then give rise to 

 other colonies. It is found from New Jersey north- 

 ward, and is very abundant in Long Island Sound. 



Colony of Corynr, 

 natural size. 



GENUS Coryne 



C. mirabilis. A hydroid about one inch high, growing in patches 

 and appearing like tufts of moss on rocks between tide-marks. When 

 highly magnified it shows club-shaped tubes with pedicels, terminating 

 in zooids, scattered over the swollen ends. The medusa-bud is larger 

 than the others and is lower on the tube. It liberates a swimming-bell, 

 which is called Sarsia. (Plate XLI.) 



Sarsia 



S. mirabilis. This medusa of Coryne is from one 

 quarter to three quarters of an inch in diameter when 

 full-grown. Its umbrella is nearly hemispherical, and 

 from the center hangs a manubrium. From the margin 

 of the umbrella hang four very long tentacles. The shape 

 of its body and the length of its tentacles and proboscis 

 are constantly changing as it moves in the water. These 

 little medusa? are very plentiful in the spring and summer, 

 and swim rapidly in all directions near the surface of 

 the water. 



GENUS Tubularia 



T. Couthouyi. This species is found in the same places 

 as Parypha crocea. The stem is three to six inches long, 

 and is inclosed in a horny sheath, which is more or less 

 ringed or jointed, or it may be smooth throughout. The 

 head, when the tentacles are expanded, measures one and 

 a half inches in diameter. It has a proboscis covered with 

 tentacles, disposed in series, which grow successively 

 shorter, the last being merely papillae. The medusa -buds 

 hang in clusters between the outer tentacles and the pro- 

 boscis. The animal grows in bunches of five to ten tubes, 

 which spring from a creeping, tangled stem. (Plate XLI.) 



GENUS Parypha 



Sarsia, the free f' crocea. This is one of the most beautiful of the tubu- 

 atedas ot coryve. larians. It has a large, drooping head on a stem three to 



