282 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



developed. No otocysts. Five pairs of nepliridia open- 

 ing on segments 5 to 9. Two or more pairs of oesophageal 

 pouches, the anterior pair long and slender or club-shaped, 

 the others shorter and usually pyriform. No pouches on 

 the first diaphragm. 



Recorded from the Mediterranean and from the west 

 coast of the United States. 



(e) A. cristata, Stimpson.* Seventeen chsetigerous 

 segments. Eleven pairs of gills, the first on the seventh 

 segment. Otocysts, closed spherical sacs each containing 

 a single large spherical chitinoid otolith. Six pairs of 

 nepliridia opening on segments 5 to 10. One pair of 

 oesophageal pouches, cylindrical or club-shaped. Dia- 

 phragmatic pouches (on the first diaphragm) large and 

 finger-shaped. 



Found in the Mediterranean, in the West Indies and 

 on the eastern shores of North America, south of latitude 

 40° N. 



II. — The characters of the ecaudate Arenicolidse are 

 as follows : — No tail, the parapodia and gills extend to the 

 posterior end of the animal. Body generally of an almost 

 uniform diameter. Number of gills variable (according 

 to age and species), gills branched unilaterally. Pros- 

 tomium simple, conical, non-lobate. Brain commissural. 

 Otocysts closed spherical sacs, otoliths spherical. Dia- 

 phragmatic pouches long and finger-shaped. (Esophageal 

 pouches, one pair, flask-shaped. Nephridia with dorsal 

 lip bearing somewhat cylindrical digitiform, often 

 branched, ciliated vascular processes, ventral lip deeply 

 notched in middle, the two halves semi-circular in shape. 

 Ova generally oval with thick vitelline membrane (5 to 6/x). 



(a) A. grubii, Claparede.* — First gill on segment 12 



* For an account of these species see Gamble, F. W. and 

 Ashivorth, J. H.~ Q.J. M.S., Vol. 43, pp. 419-569. Pis. 22-29. 



