NO. 2 HARTMAN : POLYCHAETOUS ANNELIDS 257 



Arabella iricolor (Montagu) 



Fauvel, 1923, pp. 438-439, fig. 175; Hartman, 1944, p. 242. 



At Dillon Beach, Tomales Bay and Tomales Point, this abounds in 

 mussel beds and in rocky crevices, in gravel beds and among holdfasts. 

 Length is 70 to 200 mm. 



Drilonereis nuda Moore 



Moore, 1909, pp. 254-256, pi. 8, figs. 21-23; Hartman, 1944, pp. 250- 

 251, pi. 13, figs. 297-302. 

 At Tomales Point, ocean side, and at Second Sled Road, Dillon 

 Beach, this occurs in holdfasts. It is very long and extremely slender. The 

 proboscidial armature lacks mandibles. Length is about 200 mm. 



Family Orbiniidac 

 Key to Species 



1. Prostomium anteriorly pointed, acute 2 



1. Prostomium anteriorly broadly rounded, spatulate .... 

 Naineris laevigata 



2. Ventral side of anterior end with transverse rows of papillae . 

 Orbinia johnsoni 



2. Ventral side without transverse rows of papillae 



Scoloplos acmeceps 



Naineris laevigata Grube 



Fauvel, 1927, pp. 22-23, fig. 7. 



In Tomales Bay, at Perch Rock Point and Second Sled Road, Dillon 

 Beach, this occurs with boring clams and holdfasts ; at Tomales Point it 

 is in holdfasts of narrow-leaved eel grass. In life it is orange red with a 

 brownish cast. Length is 80 to 150 mm. 



Scoloplos acmeceps Chamberlin 



Chamberlin, 1919, pp. 15-16. 



This is very common in sand flats of Tomales Bay and Bodega 

 Lagoon. It is orange red in life, and long, fragile, especially in posterior 

 parts. Length is 100 to 200 mm. Scoloplos elongata Johnson (1901, p. 

 412) is another species and goes rightly to the genus Haploscoloplos 

 Monro since it lacks uncini in thoracic neuropodia. 



