﻿I860.] 



SALTER BOLIVIAN FOSSILS. 



65 



Phacops latifrons, Bronn. (P. Bufo, Green.) PI. IV. fig. 8. 



In all essential particulars this agrees with the common Devonian 

 species known in Europe under the name P. latifrons, and in America 

 by Dr. Green's appellation P. Bufo. Comparing it with either 

 Spanish or American specimens, I see no difference, except a some- 

 what flatter axis, and perhaps one rib fewer in the tail-piece. The 

 group of Phacops to which it belongs sometimes occurs in Upper 

 Silurian strata ; but this species is nevertheless a most characteristic 

 Devonian form, and has an immense geographical range. 



Locality. Near Oruro. In a rolled pebble. 



Mr. Pentland found near the town of Aygatchi, Bolivia, another 

 Phacops, which, from its type, belongs most certainly to Devonian 

 rocks. It is one of the group Cryphceus, distinguished by having 

 the border of the tail spinose ; moreover, it is not far removed in 

 affinity from the characteristic Phacops Gaffer and P. Africanus of 

 the Cape of Good Hope. P. (Oalymene) Verneuilii of D'Orbigny 

 appears to belong to the same section, and is probably of the same 

 age. 



Phacops (Cryph^us) Pentlastdii, n. sp. PL IV. fig. 9. 



Bather more than 2 inches long, and 11 inch broad, convex, 

 long-ovate, with a subtriangular head ; the tail pointed, ribbed 

 throughout, and with a tubercular or subspinose border. 



Head | inch long, blunt-trigonal ; the glabella broad, inflated in 

 front, the forehead-lobe rhomboidal and blunt-pointed, but not over- 

 hanging; the facial suture supra-marginal. The margin itself is 

 thiu in front, thickened only round the sunken cheeks, and is cut near 

 its (spinose ?) posterior angle by the facial suture. Eye prominent, of 

 many moderate-sized lenses, set far forward, but not close to the 

 glabella. 



Body-rings (much broken) with the axis very prominent, and with 

 four spines on each ring, besides one within the fulcrum on the 

 pleura, and one (or two ?) outside it ; pleural groove deep, broad ; 

 ends of pleurae truncate. 



Tail-piece triangular, 6 lines in length, wider than long, with a 

 very convex axis reaching the tip, and marked by six or seven strong 

 riugs, the rest indistinct. The sides are about the same width as 

 the axis, with six strong curved ribs (the upper ones duplicate), not 

 furrowing the narrow border, but faintly continued on it into mar- 

 ginal tubercles. Both the lateral ribs and the axis have tubercles 

 on them. The terminal spine, if one existed, is broken off. 



There axe several Bohemian species of Phacops which resemble 

 this in the tubercular ornaments of the body ; but none that I know 

 have a tuberculato- spinose border to the tail; and this character, 

 combined with the inflated forehead-lobe, will certainly restrict the 

 fossil to either Upper Silurian or Devonian : it cannot be Carboni- 

 ferous. 



Locality. Aygatchi (Mr. Pentland, 1827). It comes, according to 

 that gentleman, from beds of the Carboniferous series ; it would ap- 



VOL. XVII. PAET I. F 



