212 



ARICIAD^. 



as it may be presumed a Dane is the best interpreter of northern 

 species. The figure of Fabricius is bad even for his period ; and it 

 has had the ill fortune to have been copied by Blainville (Diet, des 

 Sc. nat. Ivii., Atlas, pi. fig. 4) in an improved condition, misrepre- 

 senting the creature both in features and in manners. 

 (a) South Devon, George Montagu. 



Plate XVIII. Fig. 7. Cirratulus borealis of the natural size. 8. Head 

 and anterior segments much magnified. 9. A view of the mouth. 10. 

 Transverse section of a segment from the posterior part of the body. 

 11. A side view of two segments from near the middle, showing the 

 spines greatly magnified. 12. The tail. 



29. DODECACERIA. 

 Dodecaceria, Oersted, Annul. Dan. Consp. 44. 

 Char. Body lumbriciform : head undefined, conical ; the mouth 

 subterminal : branchiae filiform, a pair from the second and follow- 

 ing segments to the sixth or seventh ; none on the posterior seg- 

 ments : bristles in two separate series along each side, setaceous and 

 uncinate. 



1 . D. concharum. 



Dodecaceria concharum. Oersted, Annul. Dan, Consp. 44. f. 99. 

 Cirratulus concharum, Sars, Adriat. Havs Fauna, 17. Gruhe, Fam. 



Annel. 68. 

 Terebella ostrese, Dalyell, Pow. Creat. ii. 209. pi. 26, f, 10, 



Hab. The coralline region. Lives in tortuous cylindrical holes 

 which it has bored in the layers of bivalve shells, 



Desc. Worm, when full-grown, about an inch long, and scarcely a 

 line in diameter, somewhat bulged in the middle, about equal at both 



No. XXXVIII, — Dodecaceria concharum. 



ends, of a yellowish-brown colour, irregularly dusked, and marked 



