TEREBELLIFORMIA. 



485 



Fam. 1. Cirratulidae. Cylindrical body pointed at both ends. Prestomiuni 

 elongated, conical, without tentacles, or with two tentacles (tentacular cirri, 

 Grube). Parapodia small, with simple setae. On some of the segments the 

 dorsal cirri are long and filamentous, and function as gills. A single pair of 

 anterior nephridia ; the septa and genital ducts are repeated through the hinder 

 part of the body. Inhabit burrows. Cirratulus Lam. ; Amlouinia, Qfg. ; Chaeto- 

 zone Malmg. ; Dodccaceraea (Dodecaccria) Oerst. ; Hekaterobranclius F. Buchanan. 

 Fam. 2. Terebellidae. Body vermiform and thicker anteriorly. The 

 thinner posterior por- 

 tion is sometimes dis- 

 tinctly marked off as 

 an appendage devoid of 

 setae. The prestomium, 

 which is indistinctly 

 separated from the 

 peristomium, forms an 

 upper lip and carries 

 numerous filiform ten- 

 tacles arranged in a 

 transverse row ; it may 

 have four eye spots. 

 There are pectinate or 

 branched, rarely fila- 

 mentous, gills on one 

 to three of the an- 

 terior segments ; they 

 contain a prolonga- 

 tion of the coelom. 

 Dorsal prominences 

 (notopodia) with simple 

 setae, and ventral 

 transverse ridges (neu- 

 ropodia) with hooked 

 setae. One to three 

 1 tairs of large nephrid ia. 

 From three to twelve 

 pairs of small nephridia 

 (gen. ducts) behind the 

 diaphragm. Tubi- 



colous, tube formed of 

 foreign bodies. 



Sub-fam. 1. Amphitritinae. Almost always with gills; cephalic lobe 

 short, with numerous tentacles. Amphitrite 0. F. Mull., simple setae in 

 anterior region only, 3 pairs of gills of nearly the same size, no eyes ; 

 A. johnstoni Mlmg. Terebella L. (Fig. 396), distinguished by the small 

 size of the posterior of the three pairs of branchiae ; T. (Lanicc) conchilega 

 Pall. , English coast ; Nicolea Mlmg. , two pairs of equal gills ; Helero- 

 terebella Qtf. ; Thelcpus Letick. (incl. Hctcrophenacia Qtf., Phenacia- Qtf., 

 Neottis Mlmg., etc.), filiform gills in two segments; Euthelepus Mclnt. ; 

 Leaena Mlmg.; Lanassa Mlmg.; Loimia Mlmg.; Pista Mlmg.; Nicolea 

 Mlmg. 



FIG. 396. Terebella nebulosa opened from the dorsal side (after 

 M. Edwards). T tentacles ; A' gills ; Dg dorsal vessel or heart. 



