Description and Extramammalian Life of Crenosoma mephitidis n. sp. (Nematoda) in Skunks

Abstract

Male: 8 to 9 mm long and 0.30 to 0.35 mm wide. There are about 20 distinct cuticular folds over a region of about 1 mm of the body length. Parallel longitudinal ridges extend over the entire surface of the cuticle, but gradually decrease in distinctness toward the posterior end of the parasite. Esophagus club-shaped, 350 to 375 [ long and about 75 1 wide at its greatest diameter, being only half as wide at its junction with the intestine. A festoon of esophageal cells is inserted into the intestine. Excretory pore opens about 90 to 100 1 behind head region. Ventral to esophagus and intestine are two large cucumber-shaped cervical glands measuring over 1 mm in length. Intestine fairly straight tube, wider than the esophagus. Bursa well developed (Fig. 1), measuring outspread 300 !. Width of body of the parasite above ventral rays 150 1. Bursa notched at the ends of the ventral, posterolateral and dorsal rays. Rays springing from stout bases and well developed. Ventral rays only partially divided. Ventrolateral stouter and longer than the ventroventral. Externolateral closely situated to medioand posterolateral, as is the externodorsal. Externolateral and externodorsal of similar appearance; both end near margin of bursa. Mediolateral and posterolateral divided about half their lengths. Dorsal simple. It shows at least 2 minute papillae distally. Spicules equal in size, not over 380 1 long. Viewed dorsoventrally they appear straight; laterally seen they are slightly bent proximally. Tapering distally they end in a small knob. Both spicules closely situated together, covered by a delicate cuticular sheath, strongly connected by a chitinized thorn with a bifurcated 90 1 long accessory piece. Female: about 18 mm long and 0.6 to 0.7 mm wide. Cuticular folds extend over an area of 2.60 to 2.75 mm. Size, structure and accessories of esophagus similar in both sexes. Vulva opens about 1 mm above equator of body length. Opening of vulva simple retraction of cuticle without appendices. Vagina slightly chitinized, inserted at the middle of the kidney-shaped ejaculatory duct. Ovejector parallel to longitudinal axis of body; other parts of genital organs double as usual. Tail (Fig. 2) 140 to 150 1 long, pointed, 2 minute lateral papillae 20 1k distant from tip of tail. The thin-shelled, colorless eggs 72 [ in length and 36 1 in width. They contain fully developed first stage larvae. Host: Spilogale gracilis phenax Merriam, and Mephitis occidentalis Baird. Location: Bronchi. Locality: San Francisco and Marin County, California. Type specimens: Hooper Foundation, San Francisco.