NO. 4 HARTMAN : POLYCHAETOUS ANNELIDS 411 



Genus NOTOMASTUS Sars 



Key to Subgenera 



1. Nephridial apertures reduced to a few on the thorax, or absent; 

 hood of abdominal hooks not voluminous, beak usually with 5 

 subequal teeth (pi. 47, fig. 2) Clistomastus 



1. Nephridial apertures on the abdomen only or also on the thorax; 

 hood of abdominal hooks greatly enlarged (pi. 50, fig. 3), beak 

 variously formed Notomostus 



Subgenus NOTOMASTUS Eisig 

 Type N. latericeus Sars 



The thorax consists of 12 segments; the second to twelfth are pro- 

 vided with only pointed setae in notopodia and neuropodia. The ab- 

 domen is provided with only hooded hooks. Branchiae are absent or 

 present as eversible filaments or as noneversible vesicular pouches located 

 on or near some abdominal ridges. Nephridia are present on some or all 

 abdominal segments or also on some thoracic segments. Abdominal 

 hooks are unusual in the only 2 species available for study in that the hood 

 is greatly enlarged (pi. 50, fig. 3 and pi. 51, fig. 2) ; in one of them the 

 beak is also unique (pi. 50, fig. 3). 



Eight species have been described or recorded from the Western 

 Hemisphere, but 2 {N. luridus Verrill and N. tenuis Moore) are here 

 referred to Clistomastus (see below) and another {N. gracilis Verrill) 

 is discussed under the genus Heteromastus. Some of the remaining 5 

 species are incompletely known. They are : 



1. N. agassizi Mcintosh (1885, p. 389) off New York in 1,340 fms. 

 This remains incompletely known. See also Eisig, 1887, p. 868. 



2. N. brasiliensis Grube (1868, p. 27) from Rio de Janeiro, Brazil. 

 This is incompletely known. See also Eisig, 1887, p. 867. 



3. N. giganteus Moore, p. 227. 



4. AT", latericeus Sars. This has been reported from the northeast coast 

 of North America. See Eisig, 1887, pp. 861-863. 



5. A/', parvus Berkeley (1929, p. 312) from British Columbia. 



Extra-American species are A/", eisigi Benham (1916, p. 148) from 

 south Australia; also iV. exsertilis St. Joseph, N. formianus Eisig, and 

 N. profundus Eisig from western Europe (see Fauvel, 1927, p. 147), 



