168 LITTORINID^. 



defined by their sides being abrupt instead of shelving, 

 traverse the whorls in a longitudinal direction, and are 

 separated from each other by narrow intervals of about 

 similar width. There are no spiral striee whatsoever, but 

 a few very obscure spiral indentations are barely percepti- 

 ble just within the mouth of the umbilicus. The penult 

 whorl is moderately high, and as well as the body, which is 

 rather ample in proportion, and rounded, yet somewhat 

 narrowed, at the circumference, is ventricose, the turns not 

 being flattened or sunken at the well marked suture, but 

 abruptly swollen. The base is much rounded, and the 

 umbilicus profound, but is neither particularly large, nor 

 preceded by any peculiar channel-like concavity. Only 

 two whorls and a half remain unbroken in the specimen, 

 but judging from analogy, the volutions are few (4?) and 

 of quick increase, the spire short, and the apex obtuse. 

 The mouth of the example is a little worn at the edge, 

 but is apparently simple ; it is rather ample, occupying 

 nearly one-half the basal diameter, and more than a half of 

 the total length of the shell : it is very nearly circular, but 

 if anything, it is rather longer than broad. The pillar- 

 lip is rather narrow, and turns only in a slight degree 

 towards the umbilicus. The breadth of the example is 

 scarcely the tenth of an inch, and its length still less. It 

 was dredged by Mr. Barlee, off Tarbert in Loch Fyne. 



The figures of both the Margarita minutissima of 

 Mighels (Boston Journ. Nat. Hist. vol. iv. p. 349, pi. 16, 

 f. 5.) and of the 31. elegantissima of Searles Wood (Crag 

 Moll. vol. i. p. 184, pi. 16, f. ]) remind one of its aspect, 

 yet do not coincide in many particulars. Moller observes, 

 in reference to his own costulata^ " Animal nondum mihi 

 satis cognitum est ut novum genus hie constituere non 

 audeam ; Margaritis quidem affinis, ab illis propter peri- 



