HALICORNARIA SPECIOSA. 55 
margin with wide, rather shallow crenation ; intrathecal ridge springing from 
the anterior side of the hydrotheca about midway between the margin 
and base, and extending transversely to about the middle of its lateral 
walls. Supracalycine nematophores stout, overtopping the margin of the 
hydrotheca ; mesial nematophore reaching the margin of the hydrotheca, 
and adnate to it in nearly its entire length. 
Gronosome. — Gonangia cylindrical, with a broad, truncated summit, con- 
tracted below into a short, stout latero-basal peduncle, which springs 
from the front of the stem close to the origin of a pinna. 
Double-Headed Shot Key, from a depth of from 4 to 5 fathoms. 
Halicornaria speciosa is a strong, handsome species. The pinnx are abso- 
lutely lateral, showing no disposition to arise from the anterior aspect 
of the stem. The stem is unusually thick for a monosiphonic or non- 
fascicled form, and each of its internodes carries four nematophores, one 
just above and one just below the point of origin of the pinna at each 
side. 
The gonangia in the specimen are small in proportion to the size 
of the trophosome, and are possibly immature. 
