54 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 148 



Family TRICREPICEPHALIDAE Palmer, 1954 



Genus TRICREPICEPHALUS Kobayashi, 1935 



Type species. — Arionellus (Bathyurus) texanus Shumard. 



TRICREPICEPHALUS THOOSA ( Walcott) 



Plate 6, figures 1-4 

 Crepicephalus thoosa Walcott, 1916a, p. 214, pi, 31, figs. 1, la-k. 

 Paracrepicephalus walcotti Lochman, 1936, p. 39, pi. 9, figs. 29, 31, 33. 

 Tricrepicephalus walcotti (Lochman) Resser, 1938a, p. 102, pi. 11, fig. 54. 

 Tricrepicephalus thoosa (Walcott) Resser, 1938a, p. 101, pi. 14, fig. 8. 

 Tricrepicephalus carta (Walcott) Palmer (part), 1954, p. 755 (includes syn- 

 onymy). 



Palmer placed a number of described forms of Tricrepicephalus in 

 the synonymy of Tricrepicephalus coria (Walcott), the type of which 

 is from the House Range, Utah. He pointed out that the species con- 

 strued in this broad sense includes a considerable amount of variation. 



Since the material from the type locality for T. coria is rather poorly 

 preserved, the writer prefers to adopt for the southern Appalachians 

 form a name based on specimens from that area, and as new material 

 was collected from the type locality for T. thoosa, this is the name here 

 used. The differences between the type specimens of T. thoosa and 

 T. walcotti fall well within the range of variation in cranidial and 

 pygidial features observed in individuals from a single bed, hence 

 Lochman's name is placed in synonymy. It was also included by Palmer 

 in the list of synonyms of T. coria. 



Occurrence. — Type locality for T. thoosa is U.S.N.M. 125a, 4 miles 

 NE. of Rogersville (presumably identical with author's locality 

 cnn/1). Type locality for T. walcotti is U.S.N.M. 119, S. of Morris- 

 town. Collected by the author at localities cnk/1, cnm/2, cnn/1 to 

 cnn/5. The species ranges throughout the lower limestone member 

 {Crepicephalus zone) of the Nolichucky formation. 



Ty/>^.y.— Holotype of T. thoosa: U.S.N.M. 61654. Holotype and 

 paratype of T. walcotti: U.S.N.M. 61655, 61658. Plesiotypes: 

 U.S.N.M. 144589-91. 



Genus METEORASPIS Resser, 1935 



Type species. — Ptychoparia metra Walcott. 



METEORASPIS MUTICA Rasetti 



Plate 6, figures 13, 14 

 Meteoraspis mutica Rasetti, 1961, p. 116, pi. 21, figs. 25-29. 



The assignment of cranidium and pygidium to the same species is 

 made certain by the frequent association in the same bed observed 

 in Tennessee. The largest cranidium observed has a length of 11 mm., 

 the largest pygidium a length of 5 mm. and a width of 9 mm. 



Occurrence. — The types are from the Conococheague formation 



