DESCRIPTION OF GENERA AND SPECIES. 145 



[Angclin, pi. 18, fig. 5]. The spine of AMI pyx acuminatus is in well-preserved 

 examples longer than in Angelin's illustration. The species reminds one most of 

 Ampyx nasutus Dalman (Orthoccras limestone)." 



Doctor Freeh in his statement appears to have overlooked the fact that the 

 spine of the genus Ampyx is a spinose extension of the front of the glabella, while the 

 nasute projection of the frontal rim of Anomocarc acuminatum is from an entirely 

 different division of the cephalon of the trilobite and in no way can be correlated 

 or compared with the glabella 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 cephalon of the 

 trilobite described as Ptychoparia ? fcrnasutiis Walcott [1884, p. 49, plate 10, figs. 8, 

 86]. The glabella of the latter species is quite unlike Proampyx acuminatum, being 

 more like that of Proampyx burea. On this account it is doubtfully referred to 

 Proampyx, until a further study can be made of all the forms in which the frontal 

 border is extended into the nasute projection. 



Proampyx burea (Walcott). 



Plate 14, Figure 3. 



Plychoparia (Proampyx) burea WALCOTT, 1905, Proc. U. S. Nat. Mus., vol. xxix, p. 86. (Described 

 as a new species.) 



Cephalon, exclusive of the free cheeks, quadrilateral in outline, convex. Gla- 

 bella convex, truncato-conical in outline, with the front broadly 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 con- 

 vex 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 lobes ; they slope gently back to the postero-lateral limbs, and abruptly 

 downward in front of the narrow, rounded palpebral ridge to the frontal limb; 

 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 abruptly 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 appearance. 



The type and only specimen of the cephalon in the collection has a length of 

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



This species is clearly distinguished by the nasute-like projection on the frontal 

 rim. It differs from Proampyx acuminatum [Angelin (1854), 1878, p. 26, plate 18, 

 fig. 7] in a short frontal limb and the form of the nasute projection ; also in the form 

 of the glabella and other parts of the central portion of the cephalon. 



Formation and Locality. Upper Cambrian: (C61) A dense black limestone in 

 the uppermost limestone member of the Kiu-lung group [Blackwelder, 19070, pp. 37 

 and 41 (third list of fossils), and fig. 10 (bed 13), p. 38], 3 miles (4.8 km.) southwest 

 of Yen-chuang, Shan-tung, China. 



Collected by Li San. 



