NO. 2 HARTMAN : POLYCHAETOUS ANNELIDS 259 



Polydora giardi Mesnil 



Fauvel, 1927, p. 50, fig. 17; Hartman, 1941, p. 309, fig. 43. 



Numerous individuals are referred to this species with some hesitation 

 because they differ in their known habits from previous records. They 

 inhabit the peripheral layers of encrusting coralline algae in intertidal 

 zones, and are distinguishable at the surface of the matrix by a pair of 

 minute apertures, marking anterior and posterior ends of the irregular, 

 U-shaped burrow. They are frequently found with a cirratulid, Dode- 

 caceria fistulicola (see below), but do not penetrate so deeply in the 

 corallines. 



Total length is 12 to 15 mm, but extraction from the algae usually 

 results in imperfect specimens. There is no color on the body (preserved). 

 The prostomium is moderately developed, anteriorly bifid, with 4 tiny 

 black eyespots in trapezoidal arrangement between the palpal bases ; they 

 are easily overlooked because of their small size. The first setiger is 

 provided with dorsal and ventral fascicles of setae, which are notably 

 smaller than those following. The fifth (modified) setiger is provided 

 with a dorsal fascicle of heavy hooks accompanied by an equal number of 

 pennoned setae and a ventral fascicle of fine capillary setae. The modified 

 hooks of this segment number about 4 pairs ; they are thick, yellow, with 

 a strong, falcate fang and a thick, thumblike accessory tooth in the con- 

 cave portion. On worn hooks the distal fang and accessory tooth may be 

 almost missing. 



The sixth setiger and all notopodia of succeeding segments are pro- 

 vided with only capillary setae. Neuropodia from the seventh segment 

 have hooded hooks, numbering usually 2 or 3 in a fascicle, and with or 

 without a ventralmost seta. Branchiae are first present from the tenth 

 or eleventh segment, consist of few pairs ; they are continued posteriorly 

 to about the twenty-ninth segment. The pygidium is a thick, white, 

 collarlike ring, with middorsal notch ; it is only slightly wider than the 

 last body segment and over twice as long. 



These individuals might easily be mistaken for P. armata Langerhans 

 reported from southern California (Hartman, 1941, p. 306) because of 

 their similarity in habitat. Both bore in encrusting coralline algae in 

 intertidal zones, but in P. armata the last few segments are provided with 

 special fascicles of spines and the modified hooks of the fifth setiger have 

 a heavy flange. 



Boccardia proboscidea Hartman 

 Hartman, 1940, pp. 382-387, fig. 1 ; 1941, pp. 299-304, pis. 46, 47. 



In Tomales Bay and Bodega Lagoon, and near the mouth of Stempell 

 Creek, this is common in narrow, oblique or vertical crevices and burrow- 

 ing in soft shales. Length is 25 to 45 mm. 



