86 



5. Stylina, Fleming; Gray, Beechey Voy. = Stylifer, Brod. 



1. S. , n. s., Adams, MSS. t. 126 a. f. 3. 



2. S. , n. s., Adams, MSS. 1. 126. f. 5. 



Fam. 27. Acteonidce, p. 160. 



Teeth, central none, lateral numerous, uniform, in a diverging cross 

 series. Operculum horny, spiral, few-whorled. Shell external. 



1. Acteon, n. 292. 

 1. A. Tornatilis. Tornatella fasciata, Philippi, 1. 128. f. 5. 



Tylodina, according to Loven, is allied to this family. 



b. Operculum annular. Eyes far behind tentacula. 

 Fam. 28. Rissoellidce. 



Front of head nicked, lobes elongate cylindrical, nearly as long as 

 the tentacula. Eyes far back. Operculum half-ovate, annular ; nu- 

 cleus near the inner straight edge, with a central internal process. 



1. Rissoella, Gray, 1848, n. 286, part. 

 1. R. glaber. Rissoa? g., Alder, t. 125. f. 3. 



Order II. Scutibranchiata. 



Gill consisting of two series of lamelte, forming one or two series 

 over the back of the neck or on the under edge of the mantle round 

 the foot. Animal hermaphrodite, self-impregnating ? Shell spiral 

 or symmetrical, conical. Rectum often traversing the heart. 



This order may be thus divided : — 



Nor?nal. Heart traversed by the rectum ; lateral teeth very nu- 

 merous. Scutibranches, Cuvier, Trochina, Loven. Containing the 

 first seven families. 



Abnormal. Heart separate from the rectum. Teeth moderate 

 in number, in pairs. Containing the remaining families. 



Sect. 1. Podophthalma, p. 143. 



Eyes pedicelled, separate from the tentacula. Shell and oper- 

 culum spiral. Teeth numerous, lateral ones uniform, very numerous, 

 crowded. 



a. Sides of the foot with a continued fringe, with three or four elon- 

 gated tentacula on its upper surface. Shell internally pearly. 



Fam. 1. Turbinidee, p. 143. 



Operculum horny, with a solid, convex, calcareous coat. Frontal 

 appendages two, below the tentacula, lobed. 



a. Turbina. Mouth and oper. subcircular. 



* Oper. without spiral ridges. 



1. Sarmaticus. Oper. externally covered with numerous sepa- 



