/S. I. Smith — Cnfstacemis of the Atlantic Coast. 



105 



a result of the difterence in their habitats, the stenolepis being con- 

 fined to shallow water where the bottom is overgrown with eel-grass 

 or algae, abounding particularly among eel-grass during the summer 

 and autumn ; while the mixta is apparently confined to deeper, and, 

 at least in summer, very much colder, water, ranging from twenty to 

 a hundred or more fathoms, where there is no eel-grass and seldom, 

 if ever, algfe. 



The stenolejns is an annual species; the young appear in early 

 summer, come to maturity early in the winter, produce young from 

 mid-winter to spring, and all the mature individuals disappear before 

 the second summer, the males disappearing long before the females. 

 The following tabulation of the results of an examination of several 

 collections made at difierent seasons of the year, illustrates this fact. 



Mysis OCUlata Kroyer ex 0. Fabricius. 



Mysis spinulosus Packard, Canadian Naturalist and Geologist, vol. viii, p. 419, 1863. 

 Mysis oculata Packard. Memoirs Boston Society Nat. Hist., vol. i, p. 301, 1867. 



Labrador!, "abundant along the whole coast" (Packard). Grin- 

 nell Land, as far north as latitude 79° 29' (Miers). Greenland 

 (Kroyer, Stimpson, et al.). Iceland (G. O. Sars). Buchholz and 

 Miers each include Spitzbergen among the habitats of this species. 

 The very closely allied form, M. relicta Loven, by Professor G. O. 

 Sars regai'ded as only a variety M. oculata^ occurs in the Gulf of 

 Bothnia (G. O. Sars), in the fresh-water lakes of southern Scandina- 

 via ! (Loven, G. O. Sars), and in Lakes Michigan ! and Superior!. 



Trans. Conn. Acad.. Vol. V. 14 April, 1879. 



