468 MARPHYSA FALLAX. 
Famity KunNIcIDzA. 
MARPHYSA FALLAX, Marion & Bobretzky, 1875. Plate CXXXYV, fig. 24—head and anterior 
region, fig. 24a—foot. 
Specific Characters.—The cephalic lobe presents a median bay so as to make it somewhat 
bilobed, and it carries five tentacles, the two outer being a little shorter than the three central. 
Body of 31 mm. or more in length, with 100 or more segments, and has the general aspect 
and colour of Lysidice ninetta, the dorsum being bright red, with small points of white. The 
first segment is of a reddish violet—a tint rendered the more conspicuous by the pallor of 
the second segment. ‘The branchiz commence on the fourth or fifth setigerous segment 
(fourteenth segment, Southern), the first three or four consisting of a simple filament a little 
longer than the dorsal cirrus. The following nineteen have two filaments longer than the 
dorsal cirrus; then follow ten with a single filament. The posterior region is bare. The 
typical foot bears dorsally the branchize on the dorsal cirrus with its spine, the inferior 
division has a spine emerging at the terminal papilla of the setigerous process, and it 
separates the ventral bristles into two groups, an upper series of winged bristles curved 
and tapered distally with others brush-shaped, and a lower series of compound bristles, one 
or two having beneath them hooks with long shafts. Both kinds of bristles are bifid at the 
tip and furnished with wings. A third kind of bristle, fewer in number, has a long tapering 
terminal process articulated to the end of the shaft. The ventral cirrus is pmniform. » The 
funnel-shaped anal segment has a crenate border, and bears four cirri of different lengths 
ventrally on each side, the longest being median and the shortest imternal—in the 
Trish specimen. 
It is possible this may be a young form, and that its relationship with known species 
may yet be discovered. De St. Joseph thinks it approaches WM. sanguinea in the position 
of the branchiee, which are simple. 
SYNONYMS. 
1875. Marphysa fallax, Marion and Bobretzky. Ann. Sc. nat., 6° sér., t. 1, p. 12, pl. i, fig. 1 a—t. 
1888. if »  DeSt. Joseph. Ibid., 7° sér., t. v, p. 205. 
1914, a », Southern. Proc. Roy. Irish Acad., vol. xxxi, No. 47, p. 87, pl. viii, fig. 20. 
1922. ; » McIntosh. Ann. Nat. Hist., ser. 9, vol. ix, p. 18. 
Habitat—Under a stone at Bananagh, Blacksod Bay (Southern). Elsewhere it occurs 
at Marseilles (Marion and Bobretzky) ; Dinard, France (De St. Joseph). 
Marion and Bobretzky observe that the compound bristles with the bifid tips differ 
from those of M. sanguinea, and that the dental apparatus also diverges from that of the 
latter species in so far as six denticulations occur on the maxillee. Southern notes four ventral 
cirri on the anal segment and three spines in the ventral division of the foot. De St. Joseph 
found his examples in the dredge, and with a coloration approaching that of Lysidice ninetta. 
They were small, viz., 15 mm. in length. The bristles (Plate CXXXV, fig. 24a) resemble 
those of Marphysa Belli, but the species differs in regard to the branchie and in the form of 
the head (Plate CXX XV, fig. 24). 
