365 



Mi noli a preissiana, Philippi. 



PL xx., No. 1, x 300. , 



Dental formula oc. 1.(5. 1.5.). l.oc . Radula very fine and 

 thread-like. Of the central teeth the middle tooth is broad and 

 has a flange on each side of its base, the rest have each one cusp 

 with a line serrated edge and a single flange on its outer 

 side : the outermost differs slightly from its fellows. The single 

 lateral is small and simple. The marginals have long narrow 

 bases, and two cusps, of which the larger has a serrated edge. 



DOCOGLOSSA. 



Helcioniscus limbatus, Philippi. 

 PL xx., No. 11, x 250. 



Dental formula " ' i w ■ Radula of very great length, 

 in coils. Three central teeth, the median tooth indistinct 

 with a long cusp, the outer tooth has a single strong hook-like 

 cusp, very dark in colour. The single lateral bicuspid, one 

 large sharp cusp, and a minute one at its root. Marginals 

 three, united, the two outer small and simple, the innermost 

 with a small apical curled cusp : all have a small pointed cusp 

 at their base. 



Patella ustulata, Reeve. 



PL xx., No. 2, x 200. 



Dental formula ' ' 96 — . Radula narrow, ribbon-like. 

 Central teeth alike, with one large curved cusp on a narrow 

 small base : the median tooth is the smallest. Single lateral 

 transverse, plate-like, with four small unequal cusps. Mar- 

 ginal tooth small and simple. There are usually three 

 marginals in this genus. Dr. Paul Fischer (Man. de Conch., 

 fig. 610) shows no truly central tooth in P. vidgata,, Linne, 

 but three marginals. Cooke, Shipley, etc., op. cit., fig. 131, 

 show in P. ere f area the same number of central teeth, but 

 only two marginals. 



Patella aculeata, Reeve. 

 PL xx., No. 3, x 200. 



Dental formula 18 ^ ' " . Radula very long, cusps of 

 central and lateral teeth of a deep-red horn colour. Median 

 tooth of the five centrals slightly the largest ; each has a large 

 curved cusp nearly as big as its more transparent base. 

 Single lateral transverse, plate-like, with four unequal cusps. 

 Three marginals, with small cusps, and almost invisibly- 

 transparent. 



