NO. 3 HARTMAN : ORBINIIDAE, APISTOBRANCHIDAE, PARAONIDAE 269 



Haploscoloplos differs from Scoloplos Blainville (see below) mainly 

 in having no thoracic neuropodial uncinate or other modified setae. The 

 species of Haploscoloplos show the same relation to those of Scoloplos, 

 sensu stricto, as Naineris setosa (Verrill) (see below) does to other 

 species of Naineris Blainville. In the case of Haploscoloplos, a separate 

 generic grouping is justified because of the wide geographic range of its 

 several species and the number of species concerned (at least 10 species 

 or subspecies are congeneric). 



Key to Species of Haploscoloplos 



1. Branchiae in part branched H. cylindrifer 



1. Branchiae simple (pi. 25, fig. 2) 2 



2. Interramal cirrus (pi. 25, fig. 1) present in some posterior 

 thoracic or anterior abdominal segments 3 



2. Without interramal cirri 4 



3. Posterior thoracic and anterior abdominal neuropodia without 

 ventral cirrus (pi. 25, fig. 5) H. robustus 



3. Posterior thoracic and abdominal neuropodia with ventral 

 cirrus (pi. 25, fig. 1) H. fragilis 



4. Subpodial lobe (pi. 28, fig. 2) present on some thoracic neuro- 

 podia H. panamensis 



4. Subpodial lobe absent 5 



5. Thoracic neuropodial postsetal lobe bifid on segments 10 or 11 

 to 19 H. bifurcatus 



5. Thoracic neuropodial postsetal lobe not bifid or obscurely so 6 



6. Abdominal neuropodia with long triangular postsetal lobe ex- 

 tending distally beyond the branchial tips . . H. foliosus 



6. Abdominal neuropodia with postsetal lobe much shorter than 

 branchiae 7 



7. Thorax with 18 or more segments; branchiae present on pos- 

 terior thoracic segments ; thoracic neuropodia a low ridge with 

 a small papilla near its midlength H. elongatus 



7. Thorax consisting of 9 or 10 setigerous segments (rarely 

 more); branchiae limited to abdomen; thoracic neuropodial 

 postsetal lobe triangular 8 



8. Length of body when adult 40 mm or more H. kerguelensis 

 8. Length of body when adult 8 mm or less 



H. kerguelensis minutus 



