. Bulletin - United States National Museum. Science. UNIVERSALLY DISTRIBUTED SPECIES. 73 disappeared in one specimen ; the laterals bicuspid. He remarks that every tooth of the radiila lies alone, so that even the cutting points do not cover or disturb the basal surfaces,of the overlying rows. Schacko refers to the near alliance, in form of jaw especially, of H. pygnuca with 21. mimitissima of the genns Pimctum of Morse. Looking at the descriptions and figures of the jaws of pygmcea and minutissima, one will notice, with striking general similarity of char- acters, some differences ; on the ot
. Bulletin - United States National Museum. Science. UNIVERSALLY DISTRIBUTED SPECIES. 73 disappeared in one specimen ; the laterals bicuspid. He remarks that every tooth of the radiila lies alone, so that even the cutting points do not cover or disturb the basal surfaces,of the overlying rows. Schacko refers to the near alliance, in form of jaw especially, of H. pygnuca with 21. mimitissima of the genns Pimctum of Morse. Looking at the descriptions and figures of the jaws of pygmcea and minutissima, one will notice, with striking general similarity of char- acters, some differences ; on the other hand, the lingual teeth of the two forms appear to be the same, and the shells without variation of spe- cific value. The facts regarding the distribution of S. pygmcea, which may be treated as one of the circumpolar species, favor the opinion that Lea's specific name must be placed in the synonymy of Punctum pygmwum. Moquin-Tandon describes the genitalia of the European form to have neither dart nor multifid vesicles. Lately, in studying the jaw of Microphysa vortex from Florida, I have become convinced that I was wrong in considering the jaw of pygmcea to be related to that of the Orthalicidcc. It is quite similar to that of Microphysa.! in which genus, accordingly, I place the species. The jaw is low, wide, slightly arcuate, with blunt, squarely truncated ends; it is composed of sixteen sepa- rate pieces, each higher than wide, with slightly overlapping edges. These pieces do not run obliquely towards the middle of the jaw; there is, there- fore, no appearance of an upper median triangular piece, as in Orthali cus and Liguus. The lingual membrane is long and narrow. 1-13 teeth each. The centrals have a base of attachment much longer than wide, ex- panded below and squarely truncated, very Fig. Jaw of (Murse.) There are 54 rows of 13- FlG. Please note that these images are extracted from scanned page images that may have been digitally enhanced for re
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