Gatty Marine Laboratory, St. Andrews. 163 
from this in several particulars. The species is small, 
and it is unknown whether it is a young or an adult form, 
only a single example having been obtained, and it mea- 
sures about five-eighths of an inch in spirit, its diameter 
being about 1 mm. The general aspect is indicated in the 
sketch (Pl. VII.), though the eyes have now disappeared. 
The segments are about fifty-five in number. The head 
shows less of a basal constriction than usual in examples of 
Cirratulus cirratus of the same size. The cirri from the 
fourth segment are of great length, probably reaching in 
life beyond the tip of the tail. The latter has a similar 
termination to that of C. cirratus, the ventral papilla being ~ 
the more prominent. The caudal region thus diverges 
from Keferstein’s C. bioculatus, which possesses two well- 
marked caudal cirri. 
The dorsal capillary bristles in front are of considerable 
length, and shorter forms are continued behind these. 
Thus at the tenth foot the long slender tuft of finely- 
tapered capillary bristles with a slight curvature at the 
tip * occupies the dorsal division, whilst the ventral series 
consist of bristles having short cylindrical shafts, which 
expand into knifeblade-like tips finely tapered at the 
extremity, five being fully developed. About the twentieth 
foot the dorsal bristles are shorter but retain the same 
character, and by-and-by hooks appear in this division. 
In the ventral division they are at first accompanied by 
a bristle—indeed, occasionally a bristle is found in the 
dorsal division with the hooks + posteriorly. The hooks 
thus correspond with those of Cirratulus, and differ from 
Keferstein’s species or any allied form with the bifid 
hooks f. 
I am indebted to Mr. Southern, who has specially worked 
at the Cirratulids, for drawing my attention to the ambiguity 
of the title in the Monograph. It had escaped observation. 
A reference to the figure of the hook in the Monograph 
will show that it cannot be confounded with Keferstein’s 
species. 
3. On the British Serpulide. 
The earlier investigators of the Serpulids gave a large 
share of their attention to the calcareous tubes, founding 
species on the nature of the coils and their texture, or, 
it may be, on the structure of the opercula and branchie. 
* ‘Monograph,’ pl. cill. fig. 16, + Id. pl. ev. fig. 19. 
t Id, pl. cv. tig. 18. : 
tt? 
