xii NEREIDIFORMIA SPIONIFORMIA 32 I 



parapodium. Ephesia Ethke. (E. gracilis E. == S'phaerodorum 

 peripatus Jnstn.) is exceptional in having unjointed chaetae. 

 North Sea, Arctic Ocean, and the Channel. The family, which 

 is much modified, is allied in some respects to the Syllidae. 



Fam. 12. Ariciidae. These worms burrow in sand between 

 tide-marks. The body consists of many short segments, and is 

 nearly cylindrical. The prostomium is more or less pointed ; the 

 chaetae are all capillary ; in the first few segments they project 

 laterally but soon come to lie dorsally, and are carried by slight 

 conical papillae (supported by acicula), which are longer in the 

 middle of the body. Most of the segments carry filiform " gills," 

 representing the dorsal cirri (Fig. 137, B). 



Scoloplos armiger Miill. is extremely common on our coast. 

 It is about an inch long, yellowish, with red gills, commencing 

 about the twelfth segment. Each of the lobes of the parapodium 

 possesses an aciculum, and the chaetae are bent in a peculiar way. 

 The everted buccal region has the form of a six- or eight-rayed 

 star. The spawn of this species may be found on the shore in 

 spring as brown, pear-shaped, jelly-like masses, each with a long 

 stalk, by which the mass is fixed to the sand. In the jelly are 

 the eggs, which may be watched passing through the earlier stages 

 of development. Atlantic on both shores, even off Spitzbergen, 

 and Nova Zembla. Another representative is Theodisca mamil- 

 lata Clap., which occurs amongst the roots of Laminaria. 



Fam. 13. Typhloscolecidae} Pelagic, greatly modified forms, 

 apparently related to the Phyllodocidae, but with very uncertain 

 affinities. The prostomium is pointed and carries a pair of 

 foliaceous tentacles ; each of the first two segments bears a pair 

 of foliaceous cirri ; the remaining segments possess a dorsal 

 and a ventral pair of foliaceous cirri, with a small bunch of 

 chaetae and a single aciculum. All the cirri have peculiar rod- 

 cells. Typliloscolex Busch, Sagitella Wagner, and Travisiopsis 

 Uljanin : all small worms. North Sea Atlantic. 



Sub-Order 2. Spioniformia. 



Fam. 1. Spionidae. Mostly small worms, with small ridge- 

 like prostomium carrying a pair of eyes, but no tentacles or 

 palps. The peristomium, which extends forwards on each side 



1 Reibisch, Phyllodociden u. Typhloscoleciden d. Plankton Expcd. 1895. 

 VOL. II Y 



