OF NORTHUMBERLAND AND DURHAM. 197 
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.—ZJ. 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 Modiole imbedded in its skin. 
3. C. ampuLLa, Brug. 
Cynthia ampulla, Forb. and Hanl. Brit. Moll. 1. 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, Linn. 
Cynthia rustica, Forb. and Hanl. 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 Hanl. Brit. Moll. i. 40). 
124, MOLGULA, Forbes. 
1. M. arEenosa, Ald. and Hane. 
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 
