228 KELLIIDiE. 



who placed it in the Mya family. The Tellimya tenuis 

 of Brown seems to have been constituted from a speci- 

 men which had lost one of its cardinal or front teeth. 

 It must have been knocked out after death. Any one 

 but a conchologist may well ask why these hinge-pro- 

 cesses are called " teeth," seeing that they are not 

 homologous to the teeth of Vertebrate animals, and 

 that they are always placed at the back, instead of in 

 front, of a headless creature. But the word, whether 

 rightly or wrongly used, has now become " household " 

 and unchangeable. I hope those out of the scientific 

 pale will accept this explanation : if they are not satis- 

 fied, the Hudibrastic distich may serve their purpose — 



" To them we leave it to expound 

 That deal in sciences profound." 



To the present genus must be referred provisionally 

 the K. cycladia of Searles Wood, a rare Coralline Crag 

 shell. To this species I am now inclined to refer a 

 shell which I found in the Shetlands and named Po- 

 romya subtrigona. A description and figure of it will 

 be found in the ' Annals and Magazine of Natural 

 History/ 3rd series, January 1858, p. 42, pi. ii. f. 1. 

 I had then only a single (the left) valve, which I sent 

 to my friend Mr. Barlee for his inspection; but un- 

 fortunately the box containing it was crushed on 

 being returned to me through the post, and a few frag- 

 ments are all that remain of the original specimen. 

 Since that time I have fortunately discovered another 

 (the right) valve in my dredgings on the same ground, 

 and I have no doubt that more specimens will hereafter 

 be found. However, I do not at present consider the 

 species, or even its generic position, sufficiently esta- 

 blished to warrant its redescription . The cartilage is in- 

 ternal, and lies on the narrower and smaller side of the 



