PLANKTON OF THE GULF OF MAINE 
109 
Cod on December 29, 1920 (station 10491), had a dozen or more Metridia and as many 
Pseudocalanus, live or six large Calanus, the siphon and part of the stem of a Ste- 
phanomia, besides a considerable mass of diatoms (Phizosolenia) and some unrecog- 
nizable animal debris clasped between its thoracic legs. Several others taken at 
random from a large catch of these shrimps, made in the northeastern corner of the 
gulf on June 10, 1915 (station 10283), carried packs consisting chiefly of Calanus, 
occasionally a Euchseta, and Pseudocalanus, matted together with unrecognizable 
vegetable debris. One had a starfish larva and two eggs, probably of its own species, 
with the young nauplius almost ready to hatch out. Lest the reader think this 
omnivorous diet is at all seasonal, I may add that most of the Meganyctiphanes 
taken in the eastern basin on August 7 of that year carried loads of Calanus, Metridia, 
and Temora, with the cladoceran genus Evadne in great numbers, besides algal 
filaments and debris, the origin of which I could not determine. At Eastport, 
too, I have seen Meganyctiphanes clasping bits of herring refuse from the sardine 
factories. 
Up to very recently the method by which euphausiids gather their food had not 
been actually observed in life, but since the preceding lines were written, Lebour 
(1924a, p. 405) has described the food as “brought to the thoracic limbs by a current 
from behind, set up by the movement of the abdominal limbs, the thoracic limbs 
forming a sort of basket-like receptacle for the accumulated food.” Thus with the 
bristly armature of their legs they sweep the water for their prey just as barnacles 
do, gathering whatever copepods, Cladocera, diatoms, peridinians, or indeed small 
animals or plants of any sort, come within their reach as they dart to and fro in the 
water. 
The nourishment of the marine copepods remained a riddle until Dakin (1908) 
found that the alimentary canals of hundreds of Calanus, Pseudocalanus, Centro- 
pages, and other genera of copepods from the North Sea contained chiefly diatoms. 
He counted up to 200 diatom shells in the stomach of a single copepod, with peridin- 
ians and a green substance (previously noted by other students), apparently the remains 
of shell-less unicellular plants. Esterly (1916) has similarly described the contents 
of the guts of several hundred copepods (mostly Calanus) from San Diego, Calif., 
as consisting chiefly of Coscinodiscus and other diatoms, silicoflagellates, Dinophysis, 
Peridinium and other peridinians, and of coccolithophorids. Lebour (1922) also 
found diatoms of various species, Phseocystis, coccolitlis, and peridinians in Calanus; 
diatoms and green remains in Pseudocalanus; diatoms and flagellates in Temora; 
and Phaeocystis in Anomalocera. 
Murphy (1923, p. 450) writes that the copepod Oithona nana ate kelp and 
diatoms in the aquarium, and we have recognized remnants of Thalassiosira in sundry 
specimens of Calanus, and Thalassiosira, Chsetoceros, and Biddulphia in Metridia 
from Massachusetts Bay at the time of the vernal diatom flowering. Diatom frag- 
ments have also been detected repeatedly in the excreta of copepods, which are 
familiar objects in the catches of tow nets, but Esterly’s (1916) discovery of an oc- 
casional nauplius and copepod fragment in copepod stomachs proved that they 
are not exclusively vegetarian. Lebour (1922) has more recently found that 
the large, blue copepod Anomalocera may feed largely on micro- Crustacea, while 
