1914] Treadwell: Poly chaetous Annelids of the Pacific Coast 223 



the setae are shorter and relatively broader than the dorsal ones, each 

 with an asymmetrical wing at its end and numerous striations on 

 its surface (pi. 12, fig. 40). While the most dorsal setae of the 

 other thoracic somites are much like those of the collar setae, the ventral 

 ones have orbiculate ends (pi. 12, fig. 41). The thoracic torus is 

 provided with a row of large hooked uncinae, the apex of each being 

 finely striated but hardly produced into definite teeth, while the basal 

 portion of each is rounded and prolonged backward into a basal rod 

 (pi. 12, fig. 42). Parallel to these uncinae is a row of pennoned setae 

 (pi. 12, fig. 43). The abdominal setae are similar to those of the 

 ventral part of the collar. The uncinae are like those of the thorax, 

 but without pennoned setae. 



Collected from San Pedro. 



Type in the Museum of the University of California. 



Branchiomma disparoculatum sp. nov. 



PI. 12, figs. 44-46 



The type is thirty-five millimeters long; its thorax is seven milli- 

 meters long; and its gills are also seven millimeters long. Its body 

 is not over four millimeters wide in the widest portion of the thorax, 

 and its abdomen is of uniform diarneter except at its extreme posterior 

 end, where it narrows abruptly. There are about twenty-one gills on 

 each side, which are frequently broken and but slightly rolled at their 

 bases. Radioles have barbs extending to their very ends except in 

 those provided with eyes, when their tips are without them. In one 

 pair of radioles, each carries a large subterminal eye, while a variable 

 number of other radioles carry smaller ones which, m some cases, are 

 hardly larger than a speck of pigment. The buccal membrane con- 

 sists of two pairs of thin, leaf-like processes, of which the ventral 

 one continues, as a thin lamella, to the ventral surface of the body 

 between the collar lobes. The ends of the collar are slightly separated 

 dorsally and the dorsal part of the collar, while thick, is inconspicuous 

 owing to the rather sudden transition to its thin portion. This thin 

 part forms a fold which partly overlaps the thick portion and is then 

 continued without a break to the ventral surface where each side 

 terminates in a triangular fold extending beyond the bases of the 

 gills. 



The thorax consists of eight somites and is provided with rather 

 prominent ventral shields whose width is one-third that of the body. 



