184 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [478] 
Ascidians. 
Page. Page. 
Cynthia partita .....-.---- 311 | Molgula Manhattensis..... 311 
Bryozoa. 
Page. Page. 
Bugula turrita.......-.--- 476 ; Vesicularia dichotoma..... 476 
Escharella variabilis...-..- 476 | Alcyonidium hirsutum..... 476 
Membranipora lineata ..... 406 | Pedicellina Americana... . - 405 
RADIATA. 
Echinoderms. 
Page. 
Asterias arenicola.. .....----- eee ee eee eee cere tee ees 476: 
Acalephs. 
Page. Page. 
Obelia gelatinosa.......--- 391 | Halecium gracile........-.. 476 
O. diaphana ...----- ----- 327 | Sertularia argentea.......- 408 
O. pyriformis ....--..--- . 390 
Polyps. 
Page. Page. 
Metridium marginatum.... 329 | Sagartia leucolena..... ... 329 
PROTOZOA. 
Sponges. 
Page. Page. 
Tedania, species.....--..-- 330 | Red branching sponge..... 476 
Halichondria, sp...------- 330 
IU. 4. ANIMALS INHABITING EEL-GRASS IN BRACKISH WATERS. 
A large portion of the shallow parts of nearly all the harbors, estu- 
aries, and ponds is occupied by a dense growth of eel-grass, Zostera 
marina, in summer. This plant flourishes both on sandy and muddy 
bottoms. During the fall and winter it is mostly torn up and drifted 
away by storms, but in the spring a new crop starts up and grows very 
rapidly, the narrow, ribbon-like leaves often becoming six feet or more 
in length during the summer. 
These tracts of eel-grass are the favorite resorts of a considerable 
number of animals, which seek these places either for food or copceal- 
ment and shelter, or for both combined. Other species, including certain 
hydroids, bryozoa, and ascidians, grow attached to the leaves of the 
eel-grass. 
