196 Mr. Frcmbly on some species ofChilones 



tlieir young state, but this reproduction is very partial in this 

 tribe ; nor do I suppose that when a valve has been so materially 

 injured as to lose its power of restraint on the contracting muscles, 

 that it can retain its situation, but must be quickly displaced or 

 concealed by the valves next in succession closing up the gap. 

 Accidents of this kind, I am inclined to think, have occurred to 

 those species, which are described as having only seven valves ; 

 and it would be an advantage to the science if the possessors of 

 the seven valvcd spt'cios would take the trouble to give them a 

 minute investigation, us much valuable information may be elicited, 

 and a subject on which much doubt al present exists might be 

 decided. 



I must not, however, conclude these remarks without acknow- 

 ledging the assistance I have received from Mr. G. B. Sowerby, 

 without which I should hardly have ventured to intrude on the 

 public notice. 



* LIGAMENTO MAUGINIS SPINOSO. 



1. Chiton spiniferus. 



C. testi oblongo-ovata, ligamento marginali lato, spinifero, spinis 

 longiusculis ; valva antica radiatim grano^a; areis centralibus 

 valvarum posticarum longitudinaliter concinne sulcatis, late- 

 ralibus rotundatis, radiatim granosis. 



Tab. Supp. XVI. f. 1. 

 Syn. Ch. aculeatus. Barnes. 



tuber culiferus. Sowerby in T. C. 



Shell opaque, oblong ovate, reddish brown, glossy ; inside red- 

 dish white : valves eight, the posterior angles of which do not 

 cover the anterior ones. Anterior valve with generally nine rows 

 of raised dots diverging from the apex, but the number perhaps 

 varies with the age of the shell. Second valve rather acutely 

 beaked and carinated, longer than the five following, which are 

 striated and shaped alike ; these all rise into rather an acute beak, 

 are carinated, each side of the carina divided into two distinct 

 portions, the anterior one the largest, and bearing broad irregular 



