Mr. F. 8. Conant on Two new Chetognaths. 289 
the most part near the bottom among the alge, to which they 
have the power of attaching themselves, undoubtedly in order 
to escape observation. ‘Their colour seems to be appropriate 
to this habitat; for while most of the Chetognaths live on or 
near the surface, and are very transparent, these are opaque 
or only slightly translucent, of a yellowish-brown colour. 
The tactile prominences appear as spots of darker brown, and 
there are irregularly distributed areas having a reddish tinge, 
resembling a calcareous alga common to the region. Their 
length is 4 millim., and the breadth unusually great in pro- 
portion to the length. The caudal segment is half the total 
length. Fins 5: two paired lateral and the unpaired caudal. 
The anterior extend on each side from a point a little poste- 
rior to the abdominal ganglion to the openings of the ovisperm 
ducts. ‘The middle fins are connected with the anterior by a 
narrow area where the ovisperm ducts open, and extend along 
the caudal segment as faras the spermatic vesicles. Poste- 
riorly each is split up into four villus-like processes, which 
extend backward and downward below the level of the rest of 
the fin, and have at their tips massés of adhesive cells for 
attachment. In this splitting-up of the middle fins S. schizo- 
ptera is unlike any Chetognath described, and upon it 
accordingly the name has been based. The regularity of the 
processes in all three specimens and the arrangement of the 
adhesive cells show beyond question that the structure is 
normal. 
The caudal fin begins at the posterior margin of the sper- 
matic vesicles, and is spatulate, as in the Spadellas ordinarily. 
Jaws 8. Anterior teeth 2 or 3 on each side, according to the 
specimen; long and recurved. Posterior teeth wanting. 
Corona ciliata (Hertwig’s ‘ Geruchsorgan”’) of a peculiar 
three-cornered shape and limited to the head and neck. It is 
unlike any form heretofore figured. There are no diverticula 
from the intestine anteriorly. ‘The ovaries extend the entire 
length of the body-segment, and contain ova nearly mature, 
The ovisperm duct shows a marked difference from all other 
Cheetognaths in being connected in the posterior part of its 
course with its fellow of the other side. It runs as follows :— 
Beginning as a blind tube at the anterior end of the ovary, 
midway between dorsal and ventral surfaces of the body, it 
passes backward, at first ventral to the ovary, then lateral 
and external, to its funnel-shaped opening between the ante- 
rior and middle lateral fins. At a point a little anterior to 
the septum between body and caudal segments it gives off a 
branch of comparatively wide lumen, which seems to contain 
spermatozoa like a receptaculum seminis, and which passes 
Ann. & Mag. N. Hist. Ser. 6. Vol. xvi. at 
