366 MYRIOCHELE HEERT. 



snout, and it slopes to a peak ventrally. The cephalic and oral margins are smoothly 

 rounded and composed of ciliated cuticle and a thick glandular hypoderm beneath. 



The body, so far as observed, for no entire example has been seen, has about twenty- 

 seven segments (Malmgren) divided into an anterior and a posterior region. The anterior 

 region has three pairs of bristle-bundles — all visible at the sides of the body, and thus 

 differing from Oivenia, where the third pair are dorsal. Each bristle is nearly straight 

 and slightly tapered toward the tip, and has short spikes directed distally (Plate CX, 

 fig. 10). 



The succeeding region has both bristles and tori. The former agree with those in 

 front. The hooks (Plate CX, fig. 10a) have a posterior projection distally and are bifid. 

 The front edge of the neck inferiorly is prominent, and the neck itself is short, for the 

 shoulder soon appears, whilst the shaft is long and tapers to a filament. 



The smooth tube in the Canadian example is nearly 4 in. in length, the anterior 

 third being spindle-shaped and prolonged posteriorly into a narrow process, thus 

 differing from the tube of Oivenia. It is composed of sand- grains incorporated in a very 

 tough secretion, which also lines it internally, and to it the animal in the preserved 

 condition clings so firmly that it is difficult to secure more than a fragment. The 

 anterior end forms a conical process with a small aperture at the tip, but only the 

 extremity is free from sand-grains. Posteriorly the long narrow tube ends in an 

 aperture, and whilst the greater part of it is covered with the sand-grains in tough 

 secretion, the terminal region, which is almost filiform, is coated with soft sandy mud, 

 which often forms a mass at the tip. The external coating is composed of firmly 

 agglutinated mud in which large sand-grains are imbedded, and occasionally a few tufts 

 of GemeUaria are attached near the anterior end, the larvae having settled and grown 

 thereon. In many the wrinkles and the grains are transversely arranged on the anterior 

 or larger portion of the tube, the long, slender, posterior end not showing this feature. 

 In those with shorter tubes the sand-grains on the other hand go to the posterior end. 



A few tubes are formed of white sand-grains with black interspersed. Tubes from 

 Norway apparently belonging to this species were bristled with sponge-spicules. 



A Myriochele was found at St. Andrews in the stomach of a haddock in 1864 by E.M. 

 invested by a sandy tube. So far as can be observed in the fragmentary specimens the 

 arrangement of the bristles and the structure of the bifid hooks are identical. The size of 

 the bifid hooks is somewhat larger than in the Canadian form. 



The tube in the examples from Clew Bay, which are probably rigidly contracted, is 

 composed of minute fragments of shells, set on edge as in Oivenia, and grains of sand fixed 

 to a transparent secretion. On the other hand, those from Station 5, South West of 

 Ireland, are formed of very minute grains of fine white sand, the abundance of the species 

 on such grounds apparently indicating the suitability of the surroundings. Unless the 

 animals are extruded from the tubes in life it is difficult to secure an entire example. 



Levinsen 1 (1883) is in doubt as to whether the two species described by Hansen, 

 viz. M. Sarsi and M. Danielsseni, are not identical with the common form. 



Fauvel (1907) includes both M. Sarsi and M. Danielsseni of Hansen under this 

 species, and there is certainly considerable variation. 



1 < Vidensk. Meddel. Nat. For./ p. 148. 



