SERPULA. CHEEPER. 151 



versely especially in the furrows between the ribs : aper- 

 ture round : diameter the eighth of an inch. 



Variety. With two brovvn circular bands on the top be- 

 tween the ribs : about half the size, and found among the 

 roots of Fuci and Corallines. 



On stones and shells, v. v. 



5. Serpula heterostropha. Irregular Creeper. 

 Montagu, p. 503. no. 7- 



Shell strong, dull dirty white : spires three, reversed, 

 with three ribs running circularly round them, and roughly 

 wrinkled transversely ; the base flat and somewhat spread- 

 ing. It differs from the last, in having the volutions in a 

 contrary direction, the base a little spread, and the ribs 

 not so much raised : it is also about half the size only. 



On shells, and sea-weed, v. v, 



6. Serpula carinata. Hidged Creeper t 

 Montagu, p. 502. no. 4. 



Shell dull white, opake, regular : spires three or four, 

 the outer one with a keel-like ridge on the top, perforated 

 in the middle, a little spreading at the base : aperture 

 nearly circular. It differs from S. spirorbis in the angular 

 shape of the outer volution ; and from S. triquetra in being 

 regularly spiral : diameter half a line. 



On old shells, v. v. 



7- Serpula corrugata. Rough Creeper. 



Montagu, p. 502. no. 5. 



Shell white, rather glossy, strong, regular : spires two 

 or three, rough with transverse wrinkles, perforated in the 

 middle, and very little spreading at the base. It differs 

 from S. Spirillum in not exposing so much of the interior 

 volutions, a small portion of the second only being visible : 

 diameter the eighth of an inch. 



On schistose rocks, v. v, 



8. Serpula lucida. Glassy Creeper. 

 Serpula reflexa. Linn. Trans, v. pi. 1, f. 31, 32. 

 Shell white, transparent, quite smooth and with a glassy 

 lustre: spires two or three; reversed, sometimes placed 



laterally, 



