332 PROTULA TUBULARIA. 
of the ganglia or cesophageal connectives lie below the great muscles, and in the mid-ventral 
line is an elongated area between them. The cesophagus is clasped by strong muscular fibres, 
the circular coat of the body-wall being external. A projecting process (muscular) occurs 
on each side of the mid-ventral line. At the outer edge of the space lying below and 
external to the great dorsal muscle is a muscular band, but such is distinct from the ventral 
longitudinal muscles, which in section appear as small rounded areas on each side of the 
middle line, with the nerve-trunks (nc.) and the neural canals at their inner borders. The 
duct (so.) of the thoracic glands appears between the dorsal muscles, and further back 
the glands themselves (gl.) are at each side in the sections. 
The structure of the body-wall changes in the posterior region (Fig. 166), for the dorsal 
longitudinal muscles have spread out as thick plates on each side of the middle line, and 
end in the lateral region in massive areas of folded muscular fasciculi which have a pennate 
arrangement. A large alimentary canal occupies the centre. The ventral longitudinal 
muscles are still proportionally small, forming in sections elongated plates somewhat thicker 
externally, with the nerve-cords and their large neural canals at the inner edge. 
1. PROTULA TUBULARIA, Montagu, 1803. Plate CXV, fig. 6—tube; Plate CXVI, fig. 2— 
body ; Plate CXXI, fig. 5—branchia; Plate CXXX, figs. 7—7b—bristles and hook. 
Specific Characters.—The cephalic region has dorsally a fillet trendmg upward on each 
side to join the acutely pomted dorsal folds of the collar, which forms a continuous frill on 
the lateral and ventral edges. Branchiz in two fans, the filaments in each ranging from 
thirty to sixty; usually uncoiled in the preparations, though the tips are often curved, 
and end in free subulate processes of considerable length; pinne of moderate length, 
closely arranged in two rows, which diminish in size, to end in short papille at the base of 
the terminal process. A bilobed fillet lies dorsally between the bases of the fans, and at 
its ventral edge is a triangular process. The firm base of the branchie is pale, whilst the 
filaments are straw-coloured with a series of red granules on each side at their origin, and 
about seven red touches on the outside of the filament, the size of these increasing distally, 
the last being at the base of the terminal process, which it partly tinges. The orange-red 
touches colour the bases of the pinne so that they are reddish and then straw-coloured, the 
intermediate ones being pale. The terminal processes are subulate. The tips of the anterior 
(thoracic) feet are also of the same brick-red, the first being paler than the succeeding. A 
dark brownish line occurs along the middle of the back. 
Body broad anteriorly, tapered posteriorly ; length, 2—24 inches, 70—105 segments. 
Flattened both dorsally and ventrally, a median groove occurring in the dorsum 
anteriorly, and on the ventral surface posteriorly. The broad membranous web anteriorly 
is continuous with the dorsal fold of the collar; it passes laterally above the bristle-tufts 
—ending ventrally by fusing with the web of the opposite side behind the last bristle-tuft 
of the anterior region. It is supported by a greatly developed dorsal process of the foot. 
Anterior region of eight segments, seven of which bear bristles, the first and the last having 
glandular ventral scutes. Bristles pale golden, long, slender and finely tapered, with 
slightly curved tips, and very narrow wings. Rows of hooks borne on a ventral fillet 
toward the posterior and inner base of the bristle-tufts. Hooks translucent, with a long 
