NORTH AMERICAN EARLY TERTIARY BRYOZOA. 375 



Historical. The genus Lepralia was created in 1838 by Johnston for all the 

 incrusting species in which the frontal was calcined. This conception was followed 

 by the paleontologists until 1880, when, the zoarial classification having been recog- 

 nized as poor, Hincks applied the name Lepralia to only those species having 

 cardelles. At the time that he resurrected this old name he should have followed 

 the rules of nomenclature, but he did not do so, for under his discussion of 

 Lepralia he did not include a single one of the species originally placed there by 

 Johnston. Norman in 1905 suggested that the name Lepralia could be employed 

 only for the species of which Lepralia (Mcmbraniporella) nitida Johnston is the 

 type. 1 



The first species placed under Lepralia by Johnston was L. hyalina (Linnaeus) 

 which belongs to the earlier described genus Hippothoa Lamarck. Lepralia nitida, 

 the second species, was therefore selected by Norman as the genotype, but unfortu- 

 nately this same form had been selected by Smitt as the genotype of Membrani- 

 porella in 1873. 



The paleontologists were much disturbed by the change in meaning' attributed 

 to the name Lepralia, for the number of fossil species published by Reuss, Busk, 

 Manzoni, and others was considerable. Moreover, in 1895, Neviani changed the 

 name of Lepralia, to Hippoporina, employing it in the meaning given by Hincks. 

 Canu, as a paleontologist, adopted Hippoporina immediately. Waters thought 

 that it might be employed with restriction. In reality Neviani's genus was not yet 

 precisely established. Of the three primitive species which he introduced, Eschara. 

 foliacea Solander, 1786, is of contested generic position, Lepralia palla-siana Moll, 

 1803, .does not correspond exactly with the definition, and Lepralia adpressa Busk, 

 1854, has endozooecial ovicells. It is impossible to characterize a genus bv the 

 examination of a single function (hydrostatic in this case). Fortunately he estab- 

 lished in 1900 the true characters of the genus Hippoporina, by the publication of a 

 superb figure of Hippoporina Integra. A fossil species should not be taken as a 

 genotype if a recent equivalent species can be found. All the species of the first 

 group of Waters correspond to it exactly, and in this group Lepralia porcellana 

 may be chosen as type of the genus Hippoporina. 



In 1898 Waters thought that the genus Lepralia Hincks, 1880, might be sepa- 

 rated according to the form of the operculum. His first group was provided with 

 an operculum much contracted laterally. As mentioned before, it became the genus 

 Hippoporina. The second group was provided with an operculum with straight 

 or nearly straight borders. It is not a natural group, and two of the species,' 

 which Waters included have been chosen as genotypes by ourselves. 



HIPPOPORINA MIDWAYANICA, new species. 



Plnte 7, figs. 17-19. 



Description. The zoarium incrusts other bryozoa. The zooecia are small, 

 distinct, ovoid; the frontal is convex and smooth. The aperture bears a circular 



1 But this is not an obligation as he claims it is ; rules are not laws. See Norman, 1905, Annals and 

 Magazine Natural History, ser. 7, vol. 12, p. 99. 



