106 
S. I. Smith — Crustaceans of the Atlantic Coast. 
Stimpson (Marine Invertebrata of Grand Manan, p. 58), reports 
this species (with an ?) as “ very abundant in the waters at the mouth 
of the Bay of Fundy, swimming near the surface in swarms.” I have 
never seen specimens from the Bay of Fund} , and, during several 
seasons spent there, I have never observed any species of Mysis 
swimming at the surface, as described by Stimpson. Thysanopoda 
Norvegica and inermis , however, were found in vast numbers in pre- 
cisely the same way as the Mysis is said by Stimpson to occur, and 
it is possible that Stimpson, without making a special examination, 
mistook the vast swarms of Thysanopoda for Mysis ocidata. 
Mysis Americana Smith. 
Mtjsis Americana Smith, Report on the Invertebrate Animals of Vineyard Sound, 
Report U. S. Commissioner of Fish and Fisheries, part i, p. 552 (258), 1874. 
Great Egg Harbor!, New Jersey, 1871, — in pools on salt-marshes, 
and in great abundance in the stomachs of the ocellated flounder 
( Chcenopsetta ocellaris), the spotted flounder ( Lophosetta maculata ), 
and the shad. Stomach of shad !, Great South Bay, Long' Island, 
May 21, 1875. New Haven!, Connecticut, — abundant among sea- 
weed, etc., May, 1873 (A. E. Verrill and I). C. Eaton) ; and in great 
abundance among hydroids, etc., under wharves, May, 1875 (S. F. 
Clark) ; also dredged in 4 to 5 fathoms. Vineyard Sound !, young 
occasionally taken at the surface in summer, 1871, 1875 ; also in the 
dredge from 25 fathoms, but probably taken on the way up ; and 
common in the stomachs of shad, mackerel, and sea-herring. Port- 
land Harbor !, Casco Bay, taken at the surface and dredged in 3 
fathoms, mud, 1873. 
This species breeds during the spring and summer, and very likely 
during the larger part of the year, since the young and old are often 
found together in spring and summer. The males are nearly or 
quite as large as the females. Females carrying eggs or young vary, 
in a large lot from New Haven, from 10 to 14 mm in length, and many 
of the males in the same lot are of the latter length. One egg-carry- 
ing female from Casco Bay is only 9 - 5 mm long. 
The Americana is closely allied to M. vulgaris of Europe, but is 
very readily distinguished by the telson, the lateral margins of 
which are armed with spines of nearly uniform size in vulgaris , while 
in Americana they are armed with stout spines alternating with 
intervals of several smaller ones. There are numerous other, but less 
conspicuous differences. 
