366 



PROCEEDINGS OF THE NATIONAL MUSEUM. 



VOL. 41. 



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Fig. 4.— Trichostrongylus calcaratus. Portion 

 of bursa showing origin of dorsal ray. d. t., 

 DORSAL ray; e. d., externo-dorsal ray; p. I., por- 

 tion OF POSTERO-LATERAL RAY. 



bursa, in preserved specimens, tightly curled inward so that it is 



impossible to spread the bursa 

 out flat. Latero-ventral (I. v., 

 fig. 3) and externo-lateral {e. I., 

 fig. 3) rays closely approxi- 

 mated to one another, about 

 equal in thickness, the former 

 slightly the thicker, each much 

 thicker than the other rays. Ex- 

 terno-dorsal ray (e. d., figs.3, 4) 

 long, curving dorsalward in its 

 distal portion; proximally it is 

 thick, distally xerj slender. 

 Ventro-ventral ray {v. v., fig. 3) 

 slender, of about the same thick- 

 ness as the distal portion of the 

 externo-dorsal ray. Postero- 

 lateral (p. Z., figs. 3,4) and medio- 

 lateral (m, I., fig. 3) rays of 

 about equal thickness, the lat- 

 ter slightly the thicker, less than 

 half as thick as the externo-lateral ray, closely approximated except 

 at their tips, where they diverge 

 slightly, the postero-lateral ray dor- 

 salward and the medio-lateral ray 

 ventral ward. Medio-lateral ray 

 closely approximated to the latero- 

 ventral ray. Dorsal ray ((^. r.,figs. 

 3, 4) unites at its base with the 

 base of the right externo-dorsal 

 ray; bifurcated distally. The dor- 

 sal lobe of the bursa is not distinct 

 from the lateral lobes, and is deeply 

 emarginate between the distal 

 branches of the dorsal ray (fig. 4). 

 Distal branches of the dorsal ray 

 are very slender, with simple un- 

 branched tips. Spicules (fig. 5) 175 

 to 190 // long, nearly equal in 

 length but somewhat different in 

 shape, dark brown in color, slightly 

 curved ventralward with truncate 

 tips and without the ventral an- 

 gular projection typical of Tricho- 

 strongylus, Tip of left spicule with 

 a large beaklike process or spur projecting ventrally, and a small 



U 



OOyU. 



Fig. 5.— T richostrongylus calcaratus. 

 Spicules and gubernaculum. guh., gubek- 



NACULUM; I. sp., LEFT SPICULE; r. Sp., EIGHT 



spicule. 



