NO. 4 HARTMAN : POLYCHAETOUS ANNELIDS 421 



or Other special parapodial structures that function as such but in a far 

 posterior region both rami of the parapodia come to be somewhat elevated 

 to form vesicular lobes (pi. 47, fig. 3). 



Abdominal parapodia are well separated from one another. In 

 median segments the ridges are only slightly elevated but farther back 

 the notopodia are progressively longer and directed posteriorly. Uncini 

 in a series are few, those in the notopodia less numerous. Median seg- 

 ments have only 4 or 5 in the dorsal ramus and 6 to 10 in the ventral one. 

 Farther back the notopodium may have only 1 or 2 inconspicuous hooks 

 that are easily overlooked and the neuropodium may have 4 or 5. 



Hooded hooks are characteristic. The distal end is hooked and 

 covered with a hood that extends only slightly beyond the beaked end ; it 

 has a restricted oval aperture. The hook has a thickened shoulder ana 

 slender neck and terminates in a long fang surmounted by a crescentic 

 row of 4 or 5 short teeth. In lateral view the crescentic row gives the 

 impression of only 2 small teeth. 



Nephridial apertures are present on the thorax, in the segmental 

 grooves at the sides of the body; the first are between the seventh and 

 eighth, the last between the tenth and eleventh, setigerous segments ; they 

 number 4 pairs (pi. 47, fig. 1 ) . 



This species is herein newly referred to the subgenus Clistomasms 

 because nephridial pores, though small, are present on some thoracic seg- 

 ments. There are no specialized branchiae but in median and posterior 

 abdominal segments the parapodial ridges may be branchial in function. 

 Abdominal hooded hooks have a transverse row of 4 or 5 teeth above the 

 fang. 



Notomastus angiilatus Chamberlain is now believed to be conspecific 

 with N. (C.) tenuis since the slight differences that have been used to 

 separate them (relative thickness of thorax and abdomen and rugosity of 

 posterior segments) are characters that are believed to intergrade among 

 individuals of a species. N. tenuis Moore (1909, p. 277) was originally 

 described from San Diego, California ; it was based on a single macerated 

 individual. N. angulatus Chamberlin (1919b, p. 16) was also described 

 from southern California at Laguna Beach. It was separated from the 

 first for having a more angulate thoracic cross section but no distinct 

 morphological differences have been found between them. 



I agree with Berkeley (1942, p. 198) that branchiae and genital pores 

 are absent; however, nephridial pores have been found in posterior thor- 

 acic segments in individuals from California and Oregon; the species is 



