APOMATUS AMPULLIFERUS. 377 
1897. Apomatus globifer, Michaelsen. Polych. deutsch. Meere, p. 188 (after Théel). 
1908. Pe geniculata, Moore. Proc. Nat. Sc. Philad., p. 361. 
1909. rf sumilis, Fauvel. Assoc. Francaise Avance. Se., p. 697. 
1912. ‘ globifer, Wollebeek. Skrift. Selsk. Krist., Bd. 11, No. 18, p. 112, pl. xli, figs. 1—3; 
pl. 1, figs. 4—6. 
1913. 5 3 Augener. Zool. Anz., Bd. xh, p. 272. 
1914. 5 similis, Fauvel. Campag. Scient. Monaco, Fasc. xlvi, p. 359, pl. xxxi, figs. 44— 46. 
1917. ., a Rioja. Anél. Poligq. Cantab., p. 91. 
Habitat.—Under stones between tide-marks, St. Peter Port, Guernsey ; and under the 
same conditions at Herm, in company with the slender tubes of Pilograna. 
It also occurs in the Mediterranean (Philippi, Marion); shores of France (Fauvel) ; 
Adriatic (Marenzeller) ; Finmark (Norman) ; shores of Cantabria (Rioja). 
The collar is less developed than in Placostegus, and approaches that of Protula, but 
though narrower it is thicker, and follows a similar arrangement, as, starting from the dorsal 
edge of the fused collar and alar membrane, it passes as a continuous fold across the ventral 
aspect to the opposite side. The truncated anterior end after removal of the branchiz 
presents a somewhat rounded central elevation, with a fossa between it and the collar. 
The body of the preserved animal is somewhat stout and short, the posterior region 
being especially massive, and it tapers only a little to the slightly flattened tail. The anterior 
region has a broad alar membrane, and the mid-dorsal is distinguished by a long conical 
elevation, with the apex directed forward and a median furrow, the rest of the dorsum being 
more or less convex except in the instances where the hollows were filled with ova. The 
ventral surface is convex rather than flattened, but it has a median groove from end to end, 
with the exception of the break at the alar fold. 
The branchiz (Plate CX XXII, fig. 2c) are reddish in life and are seven in number on 
each side. They are of moderate length, somewhat soft and thick, and in the preparations 
are usually coiled and doubled. The broad filaments taper slightly toward the extremity, 
and end in a subulate process, the pmne extending almost as far—so closely do they approach 
the tip. The tissue of the filaments is lax, so that doubling readily occurs, and both they 
and the pinne have hypodermic glandular cells, the tissue of the ciliated pine being especially 
soft, and one moniliform blood-vessel is conspicuous. Instead of the firm, hyaline cuticle 
of other forms this apparently has a very thin cuticle, the cells and granules of the hypoderm 
almost reaching the surface. In this connection the occurrence of a broad membranous 
web on the filaments on each side of the pinnee in Apomatus elisabethe of the “Challenger”! 
indicates the plastic nature of the organs in this genus. 
The operculum (Plate CX XXII, figs. 2b and 2c) is a soft globular enlargement on the 
end of a branchial filament of the ordinary character as regards general structure and the 
presence of pinne. It consists of a layer of cuticle with a hypodermic granular coat internally, 
and, moreover, the globe contains several branching structures, resembling modified distal 
processes, and it may be parasitic, which extend to the free end of the operculum. While 
thus serving as a plug to the aperture the operculum would also appear to perform a respiratory 
function, and it is filled with fluid. The filament bearing it tapers little, and the pinne 
pass up to its termination. A constriction then occurs, followed by the slightly enlarged, 
* “Annelids,’ p. 514, pl. liv, fig. 4, ete. 
