206 Mr. A. Adams on the Species of Nera 
pluma. Fig. 1 exhibits the polypite exserted from the hydro- 
theca, and the pseudopodia withdrawn : a a, mesial nematophore; 
b, lateral nematophore; c, bulbous termination of the proto- 
plasmic contents of mesial nematophore, with a cluster of large 
thread-cells immersed in the protoplasm ; d, point at which the 
protoplasm of the mesial nematophore may be projected in the 
form of a pseudopodium through the lateral aperture of the nema- 
tophore into the cavity of the hydrotheca. The figure represents 
the condition in which the pseudopodial process is entirely with- 
drawn. 
Figs. 2-4. Polypite retracted and the pseudopodia in various states of 
emission: d', pseudopodia projected into the cavity of the hydro- 
theca through the lateral apperture in the mesial nematophore, 
In fig. 4, the pseudopodium has become irregularly branched : e, 
pseudopodia projected into the surrounding water from the sum- 
mit of the lateral nematophore. 
Fig. 5. Portion of a ramulus of Antennularia antennina with hydrotheca 
and exserted polypite, and nematophores; a, azygous or mesial 
nematophores ; 4, lateral nematophores in pairs; d, protoplasm 
in a state of repose, forming a spherical mass in the distal chamber 
of the nematophore ; d!, protoplasm of the azygous nematophores 
extended as a digitiform pseudopodium ; e, similar extension of 
the protoplasm of the lateral nematophores. 
XXII.—On the Species of Nezra found in the Seas of Japan. 
By Artuur Apams, F.L.S. &e. 
Tux species of Neera, properly so called, are less numerous than 
is commonly imagined. Many shells formerly regarded as be- 
longing to this genus have already been distributed among other 
tribes. For example, N. viridescens, Hinds, N. opalina, Hds., 
and N. lata, Hds., have been properly referred to Theora, a genus 
which I consider should be placed in Tellinide, in close proxi- 
mity to Abra or Syndosmya. Then, again, N. lyrata, Hds., 
N. tenuis, Hds, and N. pulchella, Ad. & Rve., have been removed 
to Raéta, a genus of Mactride; and now I shall endeavour to 
show, by an examination of the hinge-teeth and by other cha- 
racters, that N. cochlearis, Hds., and N. adunea, Gould, consti- 
tute two small groups in the immediate vicinity of Scrobicularia. 
The genus even then, when properly restricted, will exhibit 
forms so dissimilar, or dentition so peculiar, as to require to be 
thrown into three distinct groups. 
Genus Nrzra, Gray. 
Shell inequivalve, Surface of valves lamellar. Hinge with a 
prominent cup-like cartilage-pit, Right valve with a posterior 
lateral tooth. 
1. Neera elegans, Hinds, 
NN. elegans, Hds. Proc. Zool. Soc. 1843, p. 76. 
N. Moluccana, Ad. & Rve. Moll. Voy. Sam. pl. 23. f. 4. 
Hab. Mino-Sima; 63 fathoms. 
