Mr. Jeffreys on British Mollusca. Ill 



given by the author), has confirmed my impression. I believe, there- 

 fore, that this shell is a living, but minute, representative of that 

 ancient genus, hitherto considered to be long ago extinct ; and it is 

 the more interesting inasmuch as no such representative has, I be- 

 lieve, been traced in any part of the tertiary system. The Euom- 

 phalus nitidissimus has a wide range in the European seas, extending 

 from the Shetlands to Sicily, and probably far beyond these limits. 

 I lately detected specimens among some minute shells from Sardinia, 

 and I have recorded it as existing at Spezia and elsewhere on the Pied- 

 montese coast. I have no doubt that it is the Truncatella atomus of 

 Philippi ; but I cannot account for his making such a mistake as he 

 did in his memoir on the genus Truncatella of Risso in Wiegmann's 

 * Archiv fiir Naturgeschichte,' as well as in his elaborate work on the 

 Sicilian Testacea, by not only describing the animal to be exactly like 

 that of Truncatella (viz. furnished with two long tentacles, and eyes 

 placed near their external bases), but giving in the former work a figure 

 of it in accordance with that description. In the * Archiv ' for 184 1, 

 p. 54, he states, with respect to his Truncatella atomus, " Das Thier, 

 dessen Bildung ich bei einer sechszigmaligen Vergrosserung sehr 

 genau erkannte, stimmte auf das allervolkommenste mit dem der 

 Truncatella truncatula liberein." A similar mistake seems to have 

 been committed by him in saying that the animal of his Truncatella 

 littorina (our Assiminia littorea) was also similar to that of Trunca- 

 tella truncatula or Montagui, which I have elsewhere adverted to. 

 I observed among other drawings of Mollusca made by M. Deshayes 

 during his scientific visit to Algeria about fifteen years ago, but not 

 yet published, an admirable figure of this animal ; but as he did not 

 use a microscope, he failed to notice the cilia, and represented the 

 heart as seen through the transparent shell, but which I suspect 

 were the branchiae. He informed me that he found two or three 

 specimens, from which his drawing was made, at Lacalle, and that 

 the animals were preserved and deposited in the museum of the 

 Jardin des Plantes, where, however, they are not now to be found. 

 The only congener of this species is, as far as is hitherto known, the 

 Skenea 1 rota of Forbes and Hanley, which I believe is almost as 

 extensively diffused as the other. Figures 15 «, 5, in PI. III., show 

 the lingual riband of Euomphalus nitidissimus, which appears to be 

 quite as anomalous as the animal and shell, but bears some resem- 

 blance to the tongue of Akera bullata, as represented in Dr. Gray's 

 most useful * Guide to the Mollusca in the British Museum/ part 1 . 

 p. 196. f. Ill, I could not detect any divisional plates or septa in 

 the interior of the upper whorls of the shell by making a section of 

 it, although the exterior surface presented the appearance of them. 

 They are found in E. pentangulatus. I believe the E. rota was 

 known to Montagu, because in one of his letters to my late friend 

 Mr. Dillwyn, dated in 1814 or 1815, he mentions the discovery of a 

 very minute recent Ammonite-like shell which exactly corresponds 

 with the description of ^. rota. In PI. III. f. 14. is represented a 

 portion of the tongue of Skenea planorhis, to show how very different 

 it is from that of the Euomphalus. 



