Ples. 698 



182, plate 48, fig. 4, hind foot; 4.2 inches long; length of stride 

 12 inches; animal walking nearly on a straight line (plate 36, 

 fig. 3) ; fore-foot not discovered, and the animal may have been 

 a bird in spite of the resemblance of its track to those assigned 

 to Piectropterna ; but the long heel and spur at right angles, 

 are strictly lizard-like (lacertilian) features. Connecticut river 

 red sandstone. Trias. — For Hgure see p, 697. 



Piectropterna gracilis, Hitchcock, Ichthy. Mass., 1858, p. 

 109, pi. 18, fig. 3, outline of fore and hind foot tracks, more 

 slender and smaller th'an P. minitans ; pi. 48, fig. 2, an indis- 

 tinct row of them ; only certainly found at Gill, Mass. Sup- 

 plement Ichthyology, Mass., 1865, page 24, plate 17, photo- 

 graph figure 1, a fine row of foot prints on a slab of Connecti- 

 cut river red shale, in Amherst museum. Trias. — For -figure 

 see page 697. 



Piectropterna lineans, Hitchcock. Ich. Mass., p. 110, pi. 

 48, fig. 5, fore and hind foot prints of this lizard. See page 



. Tracks found on the Conn, river red shale, Wethers 



field Cove, Mass., and on Field's farm ; shown on pi. 18, fig. 5 

 (omitted). — Trias. — See page 697, 



Piectropterna minitans. Hitch. Ich. Mass. p. 108, pi. 48, 

 fig. 2 (omitted), toes narrow and pointed, length of foot 9 

 inches, of step 16 inches ; heel increasing in width backward 

 and rounded ; width of trackway 9 inches, like a lizard's ; fore 

 foot not found but undoubtedly five toed, like P. gracilis. 

 Abundant at the Wethersfield Cove ; also found at Turner's 

 Falls, Mass. Trias. 



Plectrostylus., a cast of Macrocheilus paludinaeformis ? 

 XIII. 



Plectrodus mirabilis. See for figure Onchus tenui- 

 striatus. ' 



Plesiornis giganteus^ C. H. Hitchcock, Proc. B. S. N. H. 

 Vol. 24, 1888, Dec. 19, page 126. Trias. 



Plesiornis mirabilis, Hitchcock, Supplement to Ich. Mass., 

 1865, page 35, plate 20 (natural size), a portion of which alone 

 is shown here, viz, a part of one fore foot print, and a part of 



