[487] INVERTEBRATE ANIMALS OF VINEYARD SOUND; ETC. 193 



agilis,) which it somewhat resembles in form. The color is very variable ; 

 it is often bright yellowish greet), 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, PI. XXXVII, fig. 

 279) is by far the most abundant. The Obelia geniculata is also very 

 common, attached to Laminaria and other alga3. Various Bryozoa occur 

 attached to stones and to Fucus and other alga3. The Alcyonidium 

 hispidum (p. 312) is one of the most abundant species, and usually in 

 vests the stems and fronds of Fucus vesiculosus, but also often covers 

 broad surfaces of the rocks. The A. liirsutum 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 Zooids are also much smaller. 



The Farrella familiar is is a singular and delicate species, which occurs 

 both on the under side of rocks and on algre. The body is small, fusi 

 form, attached by a long and very slender, flexible pedicel. When it 

 surrounds the stems of small alga3, the whitish pedicels project outward 

 in all directions, and thus produce the appearance of a delicate chenille- 

 cord. This is a northern and European species. It was also dredged on 

 Saint George s bank in 1872. 



List of species found on the outer roclcy shores. 



ARTICULATA. 



Crustacea. 



Page. 



Cancer irroratus 486 



Cancer borealis 486 



Panopeus depressus 312 



Panopeus Sayi 312 



Homarus Americanus. 492 



Orchestia agilis 315 



Hyale littoralis 486 



Calliopius lamusculus 315 



Gam mar us ornatus 486 



Gammarus annulatus. . 486 



Page. 



Gammarus marinus 486 



Amphithoe inaculata ... 486 



Amphithoe, sp 486 



Caprella, sp 316 



Jrera copiosa . , 486 



Idotea irrorata 486 



I. phosphorea 316 



Erichsonia nliformis 316 



Balauus balauoides. . 486 



