The river otters of the Western Hemisphere were recognized as a distinct group of related species within the genus Lutra by Pohle (1920) in his revision of the Lutrinae. Since then a need has remained for further clarification of the relationships within the group, as well as that of the group as a whole to other forms in the subfamily. A large number of specimens was compared in an attempt to determine these relationships. Materials consisted largely of skulls, but also used were skins and postcranial material, available in smaller numbers. A number of bivariate relationships of the skull and dentition were analyzed allometrically and the overall similarities of nearly all species of Lutrinae were estimated using taxonomic distance. Other qualitative and descriptive comparisons were made to complement these methods. The amount of morphological variation within known wide-ranging species and between valid sympatric species were criteria used to infer the specific status of the taxa that were compared. Results of these comparisons led me to conclude that there are probably four Recent species of river otter in the Western Hemisphere, corresponding to the North American Lutra canadensis, the Neotropical L. annectens-enudris-platensis group, the Chilean L. provocax and the southern Pacific coastal form L. felina. The latter is the most distinct species and probably represents the earliest invader of the relatively isolated Chilean faunal province. Another Chilean species, L. provocax, is more similar to the other large Neotropical forms. Evidence further suggests that the relationship of the American river otters with L. lutra and other Old World species of that genus is not as close as was formerly assumed. Aside from differences in skull and dentition, the marked differences in the known bacula may be regarded as significant evidence of their distinctness. The analysis of overall similarity suggests that Pohle's platensis group merits generic rank. Infraspecific variation was analyzed, but not in Neotropical species because of insufficient geographical representation in samples. I propose that the platensis group of Pohle be elevated to generic rank, for which the name Lontra Gray 1 843 is available, and that L. annectens, L. enudris and L. platensis represent one species, which should bear the name Lontra longicaudis Offers 1818.

The chromosomes of Sorex arcticus maritimensis are described for the first time and their banding pattern (R- and C-bands) compared with those of Sorex araneus. The results provide further evidence for the monophyletic origin of the araneus–arcticus group and clearly indicate that the primary mechanisms of chromosomal reorganization in this group have been Robertsonian and tandem translocations. The basic karyotype of S. a. maritimensis was found to differ from that of S. a. arcticus in having a different fundamental number (34 vs. 38) but the same diploid number. A full understanding of the karyotypic differences between these taxa requires further work. Whatever the exact nature of the differences, they increase the likelihood of an independent specific status for S. a. maritimensis as suggested by the results of an earlier morphometric analysis.

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Cranial measurements, standard measurements, weights, and pelage color of the lynx from Newfoundland (Felis canadensis subsolana) and the North American mainland (F. c. canadensis) were compared to assess the difference between the two forms. Of the nine bivariate cranial relationships investigated, five (zygomatic width, mastoid width, interorbital width, postorbital width, and width between the postorbital processes) were found to be significantly greater relative to condylobasal length in F. c. subsolana. Overlap in variation between the two forms is considerable, however, Standard measurements and weights do not differ significantly. In addition, F. c. subsolana has a somewhat darker pelage than the mainland form. The isolation of the insular form may be of relatively recent date, as it has diverged only slightly from mainland populations and its recognition as a separate subspecies is questionable.

A new hog-nosed skunk, Conepatus talarae n. sp., is described from cranial, mandibular, dental and post-cranial material from the Pleistocene of Talara, Northwest Peru. It is distinguished from neighbouring species by its smaller size, and from species of approximately the same size by the shape of the mandible, the constant proportion of the trigonid in the crown of Mi, the conformation of M 2 , and its geographical isolation from other similar-sized species. INTRODUCTION Modern representatives of the genus Conepatus are known from South and Central America and northwards into the southern United States (Cabrera, 1957, Hall and Kelson, 1959). Fossil representatives were first reported from South America by Ameghino who originally described Conepatus mercedensis as Triodon mercedensis in 1875, referred it to Mephitis in 1889, and finally to Conepatus in 1906, and C. cordubensis as Mephitis cordubensis in 1889, both from the Pampean (Middle to Upper Pleistocene) of Buenos Aires Province. Burmeister (1879) described C. primaevus (=Mephitis primaeva) from Buenos Aires Province, subsequently assigned to the Ensenadian by Kraglievich (1934). Rusconi (1932) described C. mercedensis praecursor from the Ensenadian of Buenos Aires Province and dated this as Middle Pleistocene. Later Reig (1952) described C. altiramus from the Chapadmalal Formation of the Barranca de Los Lobos between Mar del Plata and Miramar, also Buenos Aires Province, which he dated as Upper Pliocene but which is now considered Lower Pleistocene (Dr. Rosendo Pascual, pers. comm.), and also raised Rusconi's (1932) subspecies to a full species as C. praecursor. A non-Argentinian fossil Conepatus was reported by Boule (1920) from the Pleistocene deposits of Tarija, Bolivia, as C. cf. suffocans. This specimen is referred to C. chinga by Hoffstetter (1963). Conepatus sp. has been listed from Talara by Lemon and Churcher (1961). North American fossil material is represented by Conepatus, probably C. leuconotus mearnsi, reported by Hall (1960) from the late Pleistocene deposits of San Josecito Cave, Nueva Leon, Mexico; C. mesoleucus by Schultz and Howard (1935) from Burnet Cave, Eddy County, New Mexico; and C. leuconotus by Ray et al. (1963) from the Pleistocene deposits of Haile, Alachua County, and Williston, Levy County, Florida. An additional and excellently preserved left mandible from Haile VII, Alachua County, Florida, now in the Vertebrate Paleontology Collection of the University of Florida (No. UF 4498), was noted by Dr. Pierce Brodkorb while Ray et a/.'s paper was in press. Dr. Clayton E. Ray (pers. comm.) suspects "that it might be the mate to the scrappy right ramus that" was reported in Ray et al. (1963). The Talara material is geographically well separated from all previous records and, because of its relative abundance and good preservation, deserves description and identification.