862 The Crustacean Nebalia , [November, 



readers. The article is taken, by permission, from the advanced 

 sheets of the Twelfth Annual Report of the U. S. Geological 

 Survey of the Territories, F. V. Hayden, in charge. 1 



The species of Nebalia inhabit the sea at moderate depths. We 

 have dredged N. bipes on the coast of Labrador in from four to 

 eight fathoms, and on the coast of Puget sound we collected a 

 similar species, just below low-water mark, among fucoids. The 

 following is taken from Baird's British Entomostraca : " Otho 

 Fabricius tells us that it carries its eggs under the thorax during 

 the whole winter; that they begin to hatch in the month of April, 

 and that the young are bom in May. They are very lively, he 

 adds, and adhere to the mother, who appears then to be half 

 dead. The adult swims in a prone state, using its hinder feet to 

 propel it through the water. They are not very active. Montagu 

 informs us that when moving in the water the superior antennae 

 are in constant motion as well as the abdominal feet, but that the 

 inferior antennae are usually motionless and brought under the 

 body. They are found, according to Leach, on the south-western 

 and western coasts of England, under stones that lie in the mud, 

 amongst the hollows of the rocks ; and Mr. McAndrew dredged 

 it from a considerable depth amongst the Shetland isles." 



In Nebalia bipes the body is rather slender and somewhat com- 

 pressed, the anterior half protected by a carapace, beyond the 

 lower edge of which the broad thin phyllopodiform feet do not 

 project. 



The carapace.— The head and anterior half of the body, in- 

 cluding the thorax and four anterior abdominal segments, are 

 covered by the carapace, which on the lower edge extends below 

 the ends of the thoracic feet, covers the basal joints of the anten- 

 nae, and entirely covers the mouth parts. The sides are com- 

 pressed, and are drawn together over the body by a large but 

 rather weak adductor muscle (PI. xiv, Fig. 6), situated a little in 

 front of the middle of the thorax. There is no Jarge highly spe- 

 cialized adductor muscle connecting the two sides of the cara- 

 pace, nor any well-marked round muscular impression in the 

 carapace, such as is characteristic in the Limnadiadae; nor is 

 there any hinge, a still more characteristic feature in the bivalved 

 Phyllopods. On the contrary, as seen in PI. xm, Fig. 3, re P re " 



plates from the stones, after the Government edition was printed. To Dr. F. V. 



