216 KELLIID.E. 



Reeluz Erycina Franciscana, and Loven Montacuta 

 tenella. 



Among some small shells sent to me by Mr. Robert 

 Dawson, and collected by him on the Aberdeenshire 

 coast, is a minute single valve, which I cannot identify 

 with any known species, whether recent or fossil. Its 

 shape is obliquely triangular, with rounded margins ; it 

 is compressed, rather solid, glossy, and smooth or marked 

 only by the lines of growth ; the beaks are blunt and 

 not prominent ; the hinge-line is small and straight; 

 the teeth somewhat resemble those in the right valve of 

 Montacuta bidentata, but they are much shorter and 

 nearly on a level with the hinge-line, the tooth on the 

 broader side being considerably larger and stronger than 

 the other j the inside is nacreous, with a plain margin. 

 The shell appears to be full-grown ; but its size is barely 

 one-fifteenth of an inch in length, and rather less in 

 breadth. If more specimens are found, I would propose 

 for this species the name of Dawsoni, as a fit compli- 

 ment to its discoverer, a zealous and intelligent con- 

 chologist. 



When dredging at Falmouth in 1839 I obtained a 

 recent single valve of the species, which Searles Wood 

 described and figured in his Monograph of the Crag 

 Mollusca (Palseont. Soc. Trans. 1850, p. 131, tab. xi. 

 f. 3 a-c) as Montacuta donacina, from the Coralline 

 Crag at Sutton. I am, no less than Mr. Wood, quite 

 unable to say in what genus this curious shell should be 

 placed. My specimen is a right valve, and it has a 

 minute tubercular tooth on the longer side of a small 

 cartilage-pit. In shape it is a miniature Zenatia (a 

 genus founded by Dr. Gray), but having an external 

 ligament. 



