86 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxix. 



Anom.ocare acuiiiliiatuni is from an entirely different division of the 

 head of the trilol)ite and in no way can be correlated or compared 

 with the o-labella of Ampyx. On this account it is unfortunate that 

 the name Proampyx was given. 



A similar nasute projection of the frontal border occurs on the head 

 of the trilobite described as Ptychopariaf jyernaautus Walcott." The 

 glabella of the latter species is quite unlike that of Proamx)yx acund- 

 nafu//!^ being more like that of Proampyx Imrea. On this account it 

 is doubtfully referred to proampyx and it is left under the genus 

 Ptychoparia, with Proampyx as a subgenus, until a further study can 

 be made of all the forms in which the frontal border is extended into 

 the nasute projection. 



PTYCHOPARIA (PROAMPYX) BUREA, new species. 



Head, exclusive of the free cheeks, quadrilateral in outline, convex. 

 Glabella convex, truncato- conical in outline, with the front broadl}^ 

 rounded; surface marked by two pairs of faintly indicated furrows; 

 occipital furrow rounded, narrow, and distinct; occipital ring narrow 

 at the sides, of medium width, and slightly convex toward the center; 

 dorsal furrow of medium width rather deep and distinct. 



Fixed cheeks convex, narrow, and about one-fourth the width of 

 the glabella at the palpebral lol)es; they slope gentl}^ back to the pos- 

 tero-lateral limbs, and abruptl}" downward in front of the narrow 

 rounded ocular ridge to the frontal liml); postero-lateral limbs short, 

 marked by a shallow furrow parallel to the margin; frontal limb 

 short, and rising a short distance in front of the glabella into a nasute- 

 like extension of the frontal rim, which rises up in front of the head; 

 to the sides the frontal limb slopes abruptl}' downward and forward, 

 forming a deep wide groove with the frontal rim; frontal rim not 

 separable from the frontal limb at the sides, but rising immediately 

 in front of the glabella into a broad nasute-like process, the height of 

 which is unknown. 



Surface unknown except on the occipital ring, where it is marked 

 by irregular, raised, inosculating lines that give it a granulose appear- 

 ance. The type and only specimen of the head in the collection has a 

 length of 10 mm., exclusive of the nasute-like projection on the 

 frontal rim. 



This species is clearly distinguished hy the nasute-like projection 

 on the frontal rim. 



This species differs from Proampyx acAiminatum Angelin, in the 

 short frontal limb and the form of the nasute projection; also iu 

 the form of the glabella, and other parts of the central portions of 

 the head. 



«Moii. U. S. Geol. Surv., 1884, VIII, pi. x, figs. 8, 8b. 



