14 RUNCINID^. 



small^ slightly hooked ; uncini numerous simple hooked 

 teeth^ arranged in divergent rows throughout/^ The 

 mandible is horny and has '^ numerous rows of teeth, 

 armed with five or more finely pointed spines : viewed 

 in section, it presents a beautiful tessellated arrange- 

 ment/' 



Synonyms: — P. mirantiacus, Risso, Bertliella porosa, 

 De Blainville, P. perforatus, Philippi, and probably P. 

 elongatus, Cantraine. P. stellatus of Risso appears to 

 be the young ; and this state I also consider the P. si- 

 deralis of Loven, judging from an examination of his 

 typical specimen. Forbes very briefly described as 

 JEgean P. limacoides, P. calyptraoides, P. scutatus, and 

 P. so7'diduSj some of w^hich may also be P. plumula ; 

 but his descriptions are too much alike to distinguish 

 the species, and he did not mention the shells. 



The characters of the order Pleurobranchiata, given 

 in the 3rd volume, p. 200, require amendment. In- 

 stead of the gills invariably forming a single row, as in 

 the Bullidce, the following family has no less than three 

 rows ; and in the succeeding family there are two rows 

 of branchial leaflets, placed one on each side of the body. 



Family lY. RUNCI'NID^, {Bu7idnadoe) Gray. 



Body minute, slug-like, depressed: mayitle separated from 

 the foot by a deep groove : tentacles none : eyes sessile, placed 

 far apart towards the sides of the anterior part of the mantle : 

 foot elongated : gills consisting of three small plumes, which 

 lie under the mantle near its hinder margin : gizzard testa- 

 ceous. 



Shell none. 



