278 PART II. SYSTEMATIC ACCOUNT 



is loosely to closely coiled in others, or only a short distal end is coiled. Most 

 of the length has lateral filiform branches or pinnules, inserted in two nearly 

 regular rows along the ventrolateral edge (Fig. E133Z)); those nearest the 

 distal end are more dispersed, whereas those nearer the base (Fig. E133C) 

 are closer together and tend to be curled toward the midventral line. Each 

 pinnule is very slender and longer than the tentacle is thick. 



"The protosoma or anterior-most region of the body is short, subconical, 

 tapers forward and lacks markings; its posterior end is indicated on the 

 ventral side of the body by the insertion of the tentacle. This fusion is firm, 

 so that the two are not easily severed. 



"The second body region, the mesosoma, is considerably longer than the 

 first and is cylindrical in shape; near its anterior end it is obliquely crossed 

 by the bridle or frenulum. It is separated from the third region, or metasoma, 

 by a transverse groove. A pair of cylindrical pores is located at the sides, just 

 behind the frenulum (Fig. E133.P)." Hartman believed these to be the 

 external apertures of coelomoducts of the mesocoele, but since no such 

 coelomoducts have been seen in any species examined it is more likely that 

 they are the pores of flask-shaped glands - D.B.C. 



"The anterior end of the metasoma is characterized by the presence of 

 ventrolateral paired glandular papillae; they are so arranged that the two 

 members of a pair are separated from the successive ones by a space about 

 equal to that of the distance between the brown rings on the tube. It thus 

 seems obvious that these papillar glands are directly concerned with tube 

 secretion. This region is followed by the much longer gonadal region, 

 characterized by sparsely and irregular dispersed epithelial papillae. About 

 halfway along the length of the body two transverse series of toothed platelets 

 indicate the position of the annular region . . . The annulae are of particular 

 interest because they bear hard chitinized platelets in transverse series. Those 

 of the anterior row are incomplete and number about 38, while those in the 

 posterior row are more numerous, numbering about 44. All the toothed 

 platelets are of one kind and terminate distally in a single row of denticles 

 (Fig. Е133Я), numbering 9-13. Each toothed bristle is distally recurved so 

 that the teeth of successive bristles tend to overlap. Seen from the end the 

 the denticles form an arcuate row (Fig. E133/). The basal or embedded stems 

 are not chitinized but taper rapidly to very tenuous strands, and are so pro- 

 longed that all those of one transverse series are brought together as a fascicle 

 and carried obliquely forward to attach to the body wall. They may function 

 to anchor the animal within the tube at selected places. 



"An entire animal measures 15 mm long to the annular region, which is 



