Bulla. 



17. B. Cranchii, Leach. — B. punctura and striata. — Brit. co. geu, 



Devon, Aberdeen, Cork, etc., 60 to 100 fath., Mr. Spirally 



puncto-striated. 

 is. B. CORNEA, Lamk. — B. liydatls (as of Linn.), B. navicula, B. am.' 



pnlla, Ilaminea hydatis.—^OMiXx Brit, co., to 50 fath., C. S. Eu. 



Broad, thin. 



19. B. HYDATis, Linn. — Haminea elegans. — Guernsey and Mediterra- 



nean. Narrower and more solid than B. cornea. 



PuiLIXE. 



20. P. APEiiTA, Lji7in. — P. Bulla, Biillaa, and Lobaria a., quadrijjartita, 



guadrilobata, and Planciana. — 'Brit. co. gen., C. S. Eu. Large, 

 smooth. 



21. P. SCABRA, Mailer. — Bulla and Scaphander scabra, pectinata, 



dilatata, and caleuulifera. — Northumberland, Zetland, Ireland, 

 etc., Mc, 5 to .50 fath. N. Eu. Oblong, serrated. 



22. P. QUADRATA, S. Wood. — Bullaa and P. *t'<<(i«/««?«.— Zetland, etc., 



10 to 100 fath., R. Striated. 



23. P. CATENA, Mont. — Bulla and Biillaa c, angvMata, and punctata. 



— Brit. CO. generally, Mr., to 40 fath. Withchain-like sculpture. 



24. P. PUNCTATA, Clark. — Bulla and Bidlcea. — Devon, Swansea, Aber- 



deen, Clare. In sand, 00 fath., Mc. With punctured sculpture. 



25. P. PRUiNOSA, Clark. — Bulla and Bullcea. — Devon, Northumb., 



Hebrides, etc. Mud, 20 to 70 fath. N. Eu. 



Scaphander. 



20. S. LiGNARius, Linn. [Bulla.) — B. ohlonga. — Brit. co. generally. 

 1 to 50 fath. N. and S. Eu., C. 



27. S. zoNATUS, Turt. [Bulla.) — Young specimen taken at Zetland by 



Mr. Jeffreys, resembling older Norwegian specimens. More oval 

 than S. lignarius. Spire umbilicated. 



Aplysia. 



28. A. HYBRiDA, Sowerbi/, — Laplysia depilans, A. depilans^Vid. punctata, 



— Brit. CO. generally. Among seaweeds, to 6 fath., C. 



Pleurobranchus. 



29. P. MEMBRANACEUS, Mont. [Lamellaria) — Devon, Arran, Cork, etc. 



Low-water, Mr. Broad, flexible. 



30. P. PLUMULA, Mont. [Bulla.) — Guernsey, Devon, Skye, etc. Littoral, 



R. Narrow, less flexible. 



SriRULA. 



31. S. Peronii. — Once taken near Swansea, imperfect. 



