254 BISPIRA VOLUTACORNIS. 
Rioja (1917) gives an account of a new species, B. Linares, from the shores of Cantabria 
(Spain), but so far as can be observed from his account and figures such may only be a variety. 
A somewhat general account of the structure of a Branchiomma was given by Brunotte’ 
(1888) from examples procured on the coast of France (l’Htang de Thau). Amongst other 
features he considers the two muciparous glands opening by a single dorsal pore anteriorly 
as modified segmental organs. He terms the chordoid supporting tissue of the branchial 
region “ cartilaginous,” but his account is good. 
Lo Bianco? (1893) found an example with the distal end of a branchial filament bifid- 
each division having an eye. He also mentions having seen a specimen 2 cm. in length, 
with a trace of eyes on its filaments. 
De St. Joseph (1894) found numerous Gregarines of a fusiform outline and like Poly- 
rabdina of Mangazzini in the intestine. 
Genus CLXV.—Bispira, Kroyer. 
Amphitrite, Montagu; Sabella, Savigny ; Distylia, De Quatrefages. 
The collar forms a thick circular flap, from which each large lateral division passes down- 
ward and forward, to end in a smaller attachment at the side of the process of the first ventral 
scute. Ventral plate of each side overlaps the lamella. Branchiz arise from a firm spiral 
base, and have the basal web and ocular specks on the outer edge. Body generally large, 
widest anteriorly. Bristles of the anterior region in two groups, viz. those with narrow wings, 
and those with flattened (knife-blade) tips. Anterior hooks avicular, commencing on the 
second segment, and similar though smaller posteriorly. 
1. BisprrA voLUTACORNIS, Montagu, 1804. Plate CXIII, fig. 5—-anterior ventral aspect ; 
Plate CXV, figs. 1—1b—body, and 1le—young; Plate CXX, figs. 8—8b—body and 
anterior end; Plate CXXVIII, figs. 5—5e—bristles, hooks and branchia; Plate 
CXXXVI, fig. 22—anterior section. 
Specific Characters.—Cephalic plate after removal of the branchiz’ presents two semi- 
circles of firm chordoid tissue for the attachment of the branchiz, and two bifid curved 
flaps over the mouth. From the outer base of the firm ridges at each side of the dorsal 
groove springs the collar as a thick curved flap from which the large lateral division passes 
downward and forward, to end in a smaller attachment at the side of the process of the first 
ventral scute. Overlapping the ventral edge of the lamella is the ventral plate of each side, 
with its triangular reflected flap, the anterior surface of which is of a rich deep brownish 
purple, bordered with white. The first ventral scute has two lunate depressions upon which 
the ventral lappets of the collar rest. The scutes are continued to the posterior end as elongated 
plates on each side of the median groove. From the firm spiral base the branchie pass forward 
to the number of forty to eighty, the filaments ending in a process with a web at each side. 
' “Recherches Anat. Gen. Branchiomma, Hcole Supér. Pharmacie de Nancy,’ 2 sér., No. 16, pp. 
1—77, pls. 1 and 2. 
2 “Atti. Accad. Sc. Nap.,’ vol. v, p. 69, Tav. iu, fig. 4. 
