ZOOLOGY. obi 



analogous objections can readily be devised against those adopted, and 

 there is nothing- easier than to devise objections when the mood impels 

 to seek for new names. 



ANCIENT LINGULID^. 



In the early days of Pakieontology the name Lingula was applied as 

 the generic designation of numerous species certainly related to the 

 living representatives of that genus but distinct in many respects. Of 

 late years, however, as is remarked by Mr. Whitheld,* "it has been 

 supposed by many that the Bi\achiopodous genus Lingula, as represented 

 by Lingula anatina Lamarck, a living species, was not represented 

 among the fossil Lingulidae of the older Paleozoic formations, if any- 

 where in rocks of paleozoic age ; and there has been a growing tend- 

 ency to class all Linguloid shells of these formations under other 

 names." While this is admitted to be correct in the main, by Mr. Whit- 

 field, he thinks that he has proof of a form congeneric with or at least 

 closely related to the modern species, in shells obtained from the Tren- 

 ton limestones of Wisconsin and Miunesota. He has carefully studied 

 the muscular and vascular scars of the shell as copied in their internal 

 casts, and thinks that " these markings correspond more nearly to those 

 of L. anatina Lamarck, than do those of any other Silurian or Devonian 

 species" which he ever examined, and, "although they do not exactly 

 correspond, still are as similar as one couhl expect in widely separated 

 species. The variations consist in the position of the various muscular 

 scars, and also somewhat in the lines of the pallial sinuses and in tlie 

 ramifications of their branches." Without going into detail it is enough 

 to reniark that there certainly seems to be considerable superficial 

 resemblance between the form thus signalized and the living rei)resent- 

 atives of the family. Nevertheless the homologies are far from being 

 as close as those which prevail in all the living forms, and which, not- 

 withstanding, have been diflterentiated under two distinct genera, 

 Lingula and Glottidia. In view of the great antiquity of the type, 

 however, even the resemblance, though not very close, is noteworthy. 

 Whether the resemblance is a generic one (using the word "generic" in 

 the restricted signification) is doubtful. 



GASTROPODS. 



A NEW TYPE OF MOLLUSKS. 



A most singular type of jMollusks, and one finding no place in the 

 current works on conchology, is the genus Ncomenia of Tullberg {Solcno- 

 inis D. & K.). This is the representative of not only a distinct family 

 (Neomeniidce) but of a group which stands so lar apart from all others 



*Whitliel(l (R. P.)- On the occurreucc of the true Lbujula iu the Trentou Liiue- 

 sloues. Am. Jour. Science (3), vol. xix, i)p. 472-475. 



