568 



PROCEEDINGS OF THE NATIONAL MUSEUM 



limacina to the typical 0. borealis, as defined by Tebble, in the number 

 of branchial, postbranchial, and total number of segments. The 

 specimens from Labrador (16 branchial, 7 postbranchial, and 33 total 

 setigers) and 0. assimilis Tebble, 1953, from central California 

 (19 branchial, 4 postbranchial, and 33 total setigers) appear to 

 fall in place in the variable series. The dorsolateral anal papillae 

 vary from short, rounded to longer, digitiform depending on the 

 degree of contraction (indicated also by Hartman, 1938d, p. 107). 



Table 3. — Summary of observations on Ophelia limacina (Rathke) 



Geographic location 



Pre- 

 bran- 

 chlal 



setiger- 

 ous seg- 

 ments 



Bran- 

 chial 

 setiger- 

 ous seg- 

 ments 



Post- 

 bran- 

 chial 

 setiger- 

 ous seg- 

 ments 



Total 

 number 

 setiger- 

 ous seg- 

 ments 



Dorsolateral 



circlet anal 



papillae 



Anal setae 



Canadian Arctic 



Greenland 



Central California..- 



Typical 0. limacina accord- 

 ing to Tebble, 1952. 



Canadian Arctic... 



Arctic Alaska, Washington- 

 Oregon 



Typical O. borealis accord- 

 ing to Tebble, 1952, Brit- 

 ish waters, Atlantic. 



Labrador 



O. assimilis Central Cali- 

 fornia. 

 Range for material examined 

 Range for O. limacina (incl. 

 O. borealis, O. assimilis). 



24 



22 



23 



22 

 (18-23) 



22 



21 



20 



20 

 (16-20) 



16 

 19 



16-24 

 16-24 



7 



6 



7 

 (6-10) 



6 



6 



6 



6 

 (6-10) 



7 

 4 



6-7 

 4-7 



40 



39 



39 



39 

 (38-39) 



38 



37 



36 



36 

 (34-36) 



33 

 33 



33-40 

 33-40 



Short to rather 

 long. 



Short 



Long 



Short, blunt 



Short 



Long 



Medium long 



Long, thin 



Long 



Short- 



Short to long 



Short to long 



Short to long. 



Short. 

 Long. 

 Short. 



Short. 

 Long. 



Short to long. 

 Long. 



Long. 



(?). 



Short to long. 

 Short to long. 



The setae of the posterior segments may be short (broken off?) to 

 long. The observations are summarized in table 3. Thus I could 

 not follow Tebble in considering 0. borealis and 0. assimilis valid 

 species. The range for the material examined is 10 prebranchial, 

 16-24 branchial, 6-7 postbranchial, and 33-40 total setigers, with the 

 dorsolateral anal papillae and setae of posterior segments short to long. 



Ophelia denticulata Verrill, 1875 (tj^pe in USNM) should not be 

 referred to 0. limacina (Hartman, 1942b, p. 130). They may be 

 distinguished as follows: in 0. denticulata the deep ventral groove 

 begins on setigers 9-10, in 0. limacina it begins on setiger 7; in 0. 

 denticulata there are 9 prebranchial setigers instead of 10 as in 

 0. limacina; in 0. denticulata paired dorsal longitudinal ridges on 

 posterior few segments are absent, present in 0. limacina. 



New records: Labrador: Strait of Belle Isle, 15-20 fms., sand; 

 2 specimens, Station 15. West Greenland: Off Conical Rock, 

 20-40 fms., 1938; 1 mile northwest of Conical Rock, 1940; west side 



