[487] INVERTEBRATE ANIMALS OF VINEYARD SOUND, ETC. 193 
agilis,) which it somewhat resembles in form. The coloris very variable ; 
it is often bright yellowish green, but frequently dark green, brownish 
green, or brown. 
The Nereis virens (p. 317, Pl. XI, figs. 47-49) is very abundant in bur- 
rows beneath the rocks. The males of this species, six to ten inches or 
more in length, and of a dark green color, were found at Watch Hill, 
April 12, in great numbers, swimming about in the pools of water among 
the rocks, with an undulatory motion, and discharging their milt in large 
quantities. Various other Annelids burrow or build tubes beneath the 
stones. <A. planaria and Leptoplana folium creep over their lower sur- 
faces. 
Attached to the stems of Fucus at low-water, several Hydroids may 
usually be found, but the Sertularia pumila (p. 327, Pl. XN XVII, tig. 
279) is by far the most abundant. The Obelia geniculata is also very 
common, attached to Laminaria and other alge. Various Bryozoa occur 
attached to stones and to Fucus and other alge. The <Aleyonidium 
hispidum (p. 312) is one of the most abundant species, and usualiy in- 
vests the stems and fronds of Fucus vesiculosus, but also often covers 
broad surfaces of the rocks. The A. hirsutum is often associated with 
the preceding species on the rocks; it forms broad, thin, soft crusts, cov- 
ered with small soft prominences, but is without the spines or bristles 
seen in the latter. The Zodids are also much smaller. 
The Farrella familiaris is a singular and delicate species, which occurs 
both on the under side of rocks and on alge. The body is small, fasi- 
form, attached by a long and very slender, flexible pedicel. When it 
surrounds the stems of small algze, the whitish pedicels project outward 
in all directions, and thus produce the appearance of a delicate chenille 
cord. This isanorthern and European species. It was also dredged on 
Saint George’s bank in 1872. 
List of species found on the outer rocky shores. 
ARTICULATA. 
Crustacea. 
Page. Page 
Cancer irroratus......-.---- 486 | Gammarus marinus ...-... 456 
Cancer borealis -.....------ 486 | Amphithoé maculata....... 486 
Panopeus depressus......-. 312 | Amphithoé, sp......-.-.--.- 456 
Panopeus Sayi...-...----- . 312 | Caprella,sp........--...--- 316 
Homarus Americanus....... 492 | Jeera copiosa........--..-- 486 
Orchestia agilis ......------ 315 | Idotea irrorata..........-- 486 
Hyale littoralis ............ 486 | I. phosphorea...-.... --.- 316 
Calliopius leviusculus....-. 315 | Erichsonia filiformis....... 316 
Gammarus ornatus......-.- 486 | Balanus balanoides......-- 486 
Gammarus annulatus. ...... 486 
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