PROTULA. 331 
Anterior bristles pale golden, long, slender and finely tapered with slightly curved tips and 
narrow wings. Hooks, which commence on the second or third segment, borne on a 
narrow fillet toward the posterior and inner base of the bristle-tuft. They have a long 
and minutely serrated anterior face, ending in a sharp, conical, large fang inferiorly. 
Posterior bristles (longer) similar to the anterior, but have no evident wings. Shorter forms 
have flattened translucent tips. The hooks, which occur on lamelle, agree in structure 
with those in the anterior region. Tube long, free or fixed, calcareous and white. 
Protula of Risso was placed along with Spiromella, Blainv., under Apomatus by Philippi! 
Fig, 165.—Transverse section of Protula tubulavia in the anterior region. Letters as before. 
Fic. 166.—Transverse section of the posterior region of Protula tubularia. Letters as before. 
(1844), that is, in the group without an operculum, though a subsequent remark shows that 
Scacchi’s account of that organ was known to him. He had not seen the animal, but he 
quoted Cuvier’s note on the orange branchie. 
A feature in the structure of the body-wall in Protula tubularia is the great size of the 
dorsal longitudinal muscles. At the extreme anterior end the dorsal surface has a deep 
median groove, the rounded parts on each side indicating the projecting dorsal muscles— 
Fig. 165. The lateral regions, a, are formed by extensions of the body-wall, and bear the 
bristles in each segment. A thin circular coat lies under the hypoderm external to the dorsal 
longitudinal muscles, and it extends into the lateral regions. Sections of the posterior ends 
1 « Arch. f. Naturges.,’ Bd. x, p. 186, 1844. 
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