270 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 10 



Family Ampharetidae 



Schistocomus hiltoni Chamberlin 



Chamberlin, 1919, pp. 17-18. 



At Tomales Point, ocean side, this inhabits sand- and debris-covered 

 tubes, on under sides of rocks or in crevices. It is characterized by its 

 branchiae which include a pair of simple, cirriform, and several pairs of 

 pinnately branched structures. Length is 25 to 50 mm. 



Family Terebellidae 



Key to Species 



1. Uncini absent from thorax, or, if present, arranged in a single . 

 row 2 



1. Uncini in thorax in double rows^ from the eleventh segment . . 4 



2. With 3 pairs of branchiae, consisting of numerous filaments . . 

 Thelepus crispus 



2. Without branchiae 3 



3. Uncini absent; prostomial lobe greatly prolonged as a long flap 

 with 3 lobes Amaea occidentalis 



3. Uncini present; prostomium not so prolonged . . polycirrus 



4. Without branchiae ; peristomium with transverse rows of minute 

 eyespots Spinosphaera oculata 



4. With a single pair of branchiae, these somewhat branched (pi. 



21, fig. 29) ; with 13 thoracic setigers 



Ramex calif orniensis 



4. With 2 pairs of branchiae, these richly branched ; with 24 or 



more thoracic setigers Terebella californica 



4. With 3 pairs of branchiae 5 



5. Anterior end provided with conspicuous lateral lappets ... 6 



5. Anterior end without lateral lappets; with 17 thoracic setigers; 

 greenish in life Eupolymnia crescentis 



6. Thoracic uncini avicular (pi. 22, fig. 41 ) Pista 7 



6. Thoracic uncini pectiniform (pi. 21, fig. 28) ; anterior end with 

 2 pairs of large lateral lappets Loimia montagui 



7. Large lappets on second branchial segment ; tube with spongelike, 

 reticulated top P. elongata 



7. Large lappets on second and third branchial segments; tube with 



large overlapping membrane (pi. 25, figs. 61, 62) 



P. pacifica 



1 See Fauvel, 1927, Fig. 89d, for illustration. 



