266 FABRICIA SABELLA. 
red spots (hearts) apparently in connection with the blood-vessels. These hearts, according 
to Arnold Watson, pulsated from twenty-four to thirty-eight times per minute. The branchie, 
which have no visible web at the base, are three in number on each side, the dense series 
of pinnze arising from these main stems on each side, and all are quite pale. The pinnze 
are longer at the base of the filaments and shorter toward the tip, so that the general effect 
of the arrangement in closure of the fan is to have a fairly even series distally. They are 
ciliated internally. At their base are two short and nearly cylindrical tentacles, ciliated 
like the branchize. A single vessel occurs in each pinna in the line of the cilia, and the surface | 
has numerous palpocils. Moreover, two vascular enlargements occur at the base of the 
branchize, which have been termed hearts. Mr. Watson states that the tentacles retain 
the material collected by the branchial fans and guide it to the mouth, whilst with their 
outer surface they expel refuse which reaches them, by the dorsal groove, from the anus. 
The tips of the branchial filaments are not ciliated in the older specimens, but apparently 
Fig. 156. 
Hre. 155: 
(&uamyyyy) 
Fig. 155.—View of the ventral lip of Fabricia sabella in a young example, in which the snout is broader. 
After Arnold Watson. Enlarged. 
Fie. 156.—Outer aspect of left branchial tuft and lip of Fabricia sabella. After Arnold Watson. 
act as tentacles, and have tactile hairs. The spatulate lip serves to guide food into the mouth 
by the inner ciliated surface, and to build with its outer ciliated surface. It grasps material 
firmly, even near the tip, by its outer surface, which is closely applied to it, but whether by 
suction or otherwise is not evident (Arnold Watson). The ridge on the second segment 
does not appear to take any part in grasping material. 
In a young example the same indefatigable observer found two long straight, smooth 
filaments, which reached the tip of the branchial fan, and arising from each side of the 
mouth at the base of the ordinary filament with the swelling there. The front lip is more 
rectangular at the tip than in the adult, and the lateral extensions from it—terminating 
dorsally in slightly projecting lobes (between which the small dorsal lip enters to separate 
the branchial plumes)—give the semblance of a collar to the region. ~ 
The body is rather more than an eighth of an inch (1—2 mm.—De St. Joseph) in length, 
cylindrical throughout the greater part of its extent, then tapered toward the tail. The 
segments are thirteen in all, seven of which pertain to the anterior and six to the posterior 
region. It is more or less rounded in the preparations, but in life it is often flattened. The 
first or buccal segment has two black eyes. The general colour is brownish or straw colour. 
aA oe 
