348 JOURNAL OF WILDLIFE DISEASES, VOL 20, NO. 4, OCTOBER 1984 Received for publication 25 April 1984. ments overlapped (Fig. 1). The maximum length of P. boughtoni (range = 380-500 m) fell below the range of larvae of Pno- tostrongylus spp. from bighorn sheep (527-673 jim), but overlapped with that of 0. inacnotis (488-611 tm). Also, max- imum length of 0. macnotis overlapped with the range of Pnotostnongylus spp. from bighorns. Therefore, where the three definitive hosts are sympatric, only infec- tive larvae in the extremes of the total length range for all species can be iden- tified with confidence. Larvae of P. boughtoni can be distinguished from those of Pnotostnongylus spp. from bighorns if there is no possibility of Onthostnongylus larvae occurring in a sample. Although total length is not the most consistent morphologic basis on which to separate species of helminths, such a method is attractive in its simplicity and adaptability to field studies. Third-stage larvae of some species in the confamiliar genus Panelaphostnongylus differ in tail structure (Ballantyne and Samuel, 1984, J. Parasitol. In press). Specific structural dif- ferences may be found among Pnoto- stnongylus and Onthostnongylus infective larvae, but rapid examination of fine mor- phological details is prevented by the nearly opaque first-stage cuticle. Removal of this cuticle without damaging the larva inside, though not impossible, is extremely difficult and time-consuming. We wish to thank Brent Gray and Ju- dith Samson for assistance in exposing and maintaining snails. This study was sup- ported by the Alberta Fish and Wildlife Division, and the Natural Sciences and Engineering Research Council of Canada. Journal of Wildlife DIseases. 20(4), 1984, pp. 348-350 © Wildlife Disease Association 1984 Skrjabingylus chitwoodorum Hill, 1939 (Nematoda: Metastrongyloidea) in Striped Skunks from Northcentral Minnesota Todd K. Fuller and David W. Kuehn, Forest Wildlife Populations and Research Group, Minnesota Department of Natural Resources, Grand Rapids, Minnesota 55744, USA The nematode Sknjabingylus chit- wood onum occurs in the frontal sinuses of striped skunks (Mephitis mephitis Schre- ber) and causes progressive deformation of the frontal region of the cranium. The frequency of lesions and degree of defor- mation were related to relative age and geographic distribution of skunks (Kirk- land and Kirkland, 1983, Can. J. Zoo!. 61: 2913-2920). There are, however, no pub- !ished accounts relating skull lesions to ac- tual ages of striped skunks, nor is there documentation of how numbers of worms relate to age and degree of deformation. This note presents age-specific documen- tation of prevalence of lesions and num- bers of adult S. chitwoodorum in the fron- tal sinuses of striped skunks from a forested region in northcentral Minnesota. Skunks were collected in the northeast- ern portion of Itasca County, Minnesota (47#{176}52’N, 93#{176}22’W). In Grand Rapids, 50 km southwest of the study area, mean Jan- uary temperature is -14 C, and in July the mean is 19 C (U.S. Dept. Commerce, unpubl. data). Snow cover is usually pres- ent from December through early April, and during the winters of 1970-1971 through 1982, mean January-March snow depth was 46 cm. Total annual precipi- tation averages 29.9 cm. Downloaded from http://meridian.allenpress.com/doi/pdf/10.7589/0090-3558-20.4.348 by guest on 10 December 2021