2 PROCEEDINGS : BOSTON SOCIETY NATUR AL HISTORY. 
In the prosecution of this work on the adult and immature Nau- 
slionia, I wish to express my especial indebtedness to Dr. H. C. 
Bumpus, of the American museum of natural history, and to Mr. 
G. M. Gray, collector for the Marine biological laboratory, for the 
loan of specimens of the rare adult. 
Naushonia crangonoides Kingsley. 
Length of male, 26 mm.; of female, 36 mm. 
Carapace (pi. 1, figs. 1, 2, 4) cylindric, depressed in front, not 
pubescent; dorsal and branchial areas sharply defined by prominent, 
straight, longitudinal groove (si) or “linea thalassinica ”; dorsal 
area truncate posteriorly, gastric region not much longer than car¬ 
diac, cervical groove (sc) well marked in middle, weak at sides, 
more distinct in the male; branchial areas widely rounded posteri¬ 
orly, anteriorly with indications of a vertical groove in forward 
fourth, and of a horizontal groove dividing the resulting antero- 
branchial area, these grooves not visible in the female; anterior 
borders of carapace finely serrate, other borders entire; external 
notch well marked; antennal spine present; carapace smooth 
except along grooves and ridges, and in dorsal and antero-branchial 
areas, which are dotted with fine tubercles visible under a lens; 
supra-orbital keel (sor) short, weak; within this another keel; an 
indistinct median keel along posterior six sevenths of back; supra- 
antennal spine minute; rostrum broadly triangular, flat, extending 
beyond eyes ; borders recurved, finely serrate, beset with fine hairs. 
Epistoma free, in shape an isosceles triangle, apex serrate, borders 
hairy. Sterna, where visible, flat. Genital openings indistinct, in 
coxa of male, and coxal joint of female. 
Abdomen (pi. 1, fig. 1) a third longer than carapace, without 
caiinae or spines, epimera moderate ; smooth, except for microscopic 
tubercles on sixth segment and telson; epimeral borders of first 
and sixth segments truncate, of other segments rounded, borders 
entiie, with fine hairs; in female, with long hairs on inner face of 
epimera near margin ; dorsal borders of segments truncate ; sterna 
impelrectly calcified; telson (pi. 1, fig. 3) a third longer than broad, 
tubercles on surface projecting backward; tip regularly rounded; 
outer third of border with fringe of long hairs; no spine at external 
