OF NORTHUMBERLAND AND DURHAM. 103 



the tunic with cylindrical convolutions. Branchial sac thin, 

 with about ten longitudinal folds, and finely reticulated ; the 

 longitudinal fibres strongest. Length nearly an inch ; breadth 

 half an inch. 



From the fishing boats at Cullercoats, with the last but less 

 common. — J. A. 



This species differs from the preceding in having both the 

 apertures terminal, and placed near together, as well as in 

 the minute granulations of the surface. It is capable of 

 greater contraction and elongation than most of the other spe- 

 cies, and in the two states might be taken for different animals. 

 It has sometimes small corallines attached, but we have not ob- 

 served any Modioloe imbedded in its skin. 



3. C. AMPULLA, Brug. 



Cynthia ain^yulla, Forb. and Hani. Brit. Moll. i. 40. 



Brought in on the fishemen's lines at Cullercoats. — J. A. 



This species which has hitherto been overlooked as British, is 

 not uncommon with us. It is unattached and cased in a thick 

 coat of sand, held together by the long slender hairs of its tunic, 

 assisted by a glutinous secretion. Its proper characters cannot 

 be observed without removing the sand, which is sometimes 

 equal in bulk to the whole of the animal. The long cylindrical 

 tubes are often beautifully streaked and spotted with carmine. 



4. C. RUSTicA, L'mn. 



Cynthia rustica, Forb. and Hani. Brit. Moll. i. 39. 



Common on stones, and at the roots of the larger sea-weeds, 

 between tide-marks, and a little beyond, 



A small, lenticular, red Cynthia, which we have always taken 

 for the young of this species, is common in similar situations. 

 This, we believe, is the C. grossularia of Van Beneden (Forb. 

 and Hani. Brit. Moll. i. 40). 



124. MOLGULA, Forbes. 

 1. M. ARENOSA, Aid, and Ilanc. 



Body nearly globular, hyaline, rather glossy, smooth to the 

 naked eye, but appearing very slightly rugose under a magnifier; 

 unattached. Apertures very close together, sublateral, tubular, or 



