168 



PIONOSYLLXS (SYLLIS) HYALINA. 



terminal pieces are rather long and boldly bifid at the tip, the edge below being spinous. 

 As usual, the spinous edge with the hooks at the tip is directed upward. 



The observation of Langerhans that in the caudal segments a simple bristle occurs 

 dorsally and ventrally, in addition to the ordinary jointed ones, is correct. A stout, 

 translucent, simple bristle (Plate LXXVIII, fig. 9a) tapered dis tally, occupies the dorsal 

 margin, and apparently another ventrally. Toward the tip of the tail the ventral 

 bristles and their terminal pieces are longer and more slender. The foot in this region 

 has a single, powerful, translucent spine, the sharp point of which projects beyond the 

 tissues. 



Reproduction. — Ehlers states that in July at Zurkowa the eggs were bluish- violet. 

 Marenzeller describes the eggs as deep rose-red, and as filling eighteen segments behind 

 the fifty-second. 



In the structure of the bristles this form leans to Pionosyllis, and it may in the 

 meantime be placed in that group. 



Grube considered that this species approached 8. moniliformis, and he states that the 



Fig. 54. — Transverse section of the body- wall of Pionosyllis (Trypanosyllis) hyalina, Grube ; d. m. dorsal 

 longitudinal muscle ; d. v., dorsal vessel ; v. v., ventral vessel ; s. o., segmental organ. Other letters as 

 before. After Malaquin. 



proboscis (Russel) reached the tenth segment (in spirit), whilst the stomach extended 

 between this and the nineteenth foot. 



Claparede, in 1864, describes the same species (as 8. simillima) from Port-Vendres, 

 and states that the eggs are bluish. He gives an amended figure in his later work on 

 Neapolitan Annelids (1868), showing ciliated grooves on each side of the head posteriorly, 

 and he points out that the tips of the spines are truncated, and the tips of the bristles 

 bidentate. 



Ehlers described, also from the Adriatic, this form under the name of Syllis pellucida, 

 though he pointed out its near approach to Grube's Syllis hyalina. The differences in the 

 shape of the ventral cirrus and in the length of the proventriculus are not material, and 

 Grube had overlooked the details of the armature of the proboscis. 



There is doubt concerning the Syllis borealis of Malmgren (1867), for while there is 



