378 APOMATUS AMPULLIFERUS. 
though short, opercular pedicle, which is again slightly constricted at its junction with the 
operculum. In an example from St. Peter Port the operculum showed no branching filaments, 
so that these in all probability are branching algoid parasites. Marion and Bobretzky allude 
to a second operculum on another of the filaments. Apomatus assimilis differs in having 
“ erystallins ” on the branchial filaments, but perhaps this is only a variety of the above, 
which sometimes shows pigment-specks at the base of the branchiz. A second small oper- 
culum is occasionally observed in those from the Channel Islands—arising as in the case of 
the larger from the tip of a branchial filament. 
The anterior region carries six setigerous processes (the first bristles being dorsal) on the 
ventral side of the alar membrane, and six elevated rows of hooks to their ventral edge. All 
the lateral bristles are directed upward and backward, and have a uniform structure (Plate 
CXXXII, fig. 2), viz., a straight shaft, narrowed at the insertion, then remaining cylindrical 
to the curvature at the tip, after which it tapers to a fine point. Serrated wings commence 
a little below the curvature, widen, and then diminish distally. 
The first bristles, which form two conspicuous tufts, present two series, a stronger and 
a more slender kind. The former has a stout shaft, curved backward at the tip, and with 
somewhat broad wings. The latter has a slender shaft, the tip is less curved, and the wings 
are narrow. Both are finely tapered at the tip. These bristles slant obliquely forward 
and outward from a point a little im front of the first lateral tuft. Though slightly longer, 
they thus have the same structure as those which follow. 
Bristles are absent in the first part of the posterior region, only about twelve to fifteen 
of the terminal segments having a pair of bristles on each side. The more anterior of these 
(Plate CX XXII, fig. 2a) have short, straight shafts and sickle-shaped tips, the broad tapering 
blade having its edge serrated. Toward the tip of the tail, however, the terminal blade is 
knife-shaped and less curved, a slight enlargement occurring at the end of the shaft. Faint 
strize in all cross the tip obliquely from the serrations. Just in front of the tip of the tail 
a series of longer and more slender simple bristles occur on each side, the finely tapered tips 
showing no apparent differentiation in the preparations. Marenzeller’s indication of a joint 
has not been observed. 
The anterior hooks (Plate CX XXVII, fig. 19) are very diaphanous, with a straight; 
minutely serrated anterior margin ending inferiorly in a slightly projecting and modified 
(blunt) main fang—below which a gulf occurs above the prow. The crown is rounded, comes 
abruptly from the anterior edge, and the posterior outline has a deep indentation. The 
body of the hook is faintly striated from the anterior face to the base, the outline of the 
latter trending in a semicircle to the posterior indentation. The anterior edge is rough, and 
the teeth so minute as to be seen with difficulty in the preparations. The posterior hooks 
have the process at the crown somewhat narrower, and the curve to the posterior border 
more abrupt, whilst the -body of the hook is smaller and the basal outline less convex. These 
hooks, as observed long ago, closely approach those of Protula in outline and general structure. 
Reproduction.—In an example procured at Herm in August numerous ova occurred in 
the hollows of the body in the tube, so that in all probability they are developed there. 
The white tube is more or less sinuous or curved, though in some it is coiled, and shows 
on its upper surface two slight longitudinal grooves with a flattened ridge between them, 
and various circular ridges of growth. The aperture is smoothly rounded, and the tube 
