PATELLID^E. 229 



mis of the girdle in C. marmoreus displays under the 

 microscrope a coverlet ornamented with erect spinules. 

 I have not succeeded in detecting any such armature in 

 British specimens ; the margin of the girdle is fringed 

 in this way, hut the surface is merely pustulated. Spe- 

 cimens taken by Captain Bedford in Mull are more than 

 an inch and a half long. 



It is the C. punctatus of Strom, who nearly a cen- 

 tury ago showed the resemblance between the animal 

 of Chiton and that of Patella ; perhaps in strictness the 

 specific name given by him, being the more ancient, 

 ought to be preferred to marmoreus. Fleming called it 

 C. IcsvigatuSj Lowe C. latus, Bean C. pictus, Couthouy 

 C. fulminatuSj and Leach C. Flemingius. 



Order II. PEC'TINIBRANCHIA'TA. 

 Family I. PATEL'LID^E, (Patelladce) Guilding. 



BODY senrioval, more or less raised above and flat beneath : 

 mantle thin, covering the back and sides : head snout-like, 

 furnished with a pair of horny jaws and a long and slender 

 tongue, which bristles with numerous teeth and is folded up 

 within the body : tentacles spike-shaped : eyes on protuber- 

 ances at the outer bases of the tentacles, wanting in cer- 

 tain kinds : gills forming a single row or plume of leaf-like 

 plates, which issue from behind the neck on the right-hand 

 side : foot very large and rounded, occupying the whole of the 

 under side. 



SHELL conical or cap-shaped ; apex turned towards one end, 

 spiral, and slightly twisted on one side, or curved, in the young 

 state : mouth extremely wide, forming the entire base of the 

 cone : central scar inside shaped like an amphora. 



This family constitutes the vanguard of the innumer- 

 able limpet tribe. Their shells are never symmetrical, 



