75 
bent down; axis smooth in the centre, with transverse marking at the 
sides; 14 joints; 8 pleurae. 
This is a doubtful species of Cryptonymus, but placed here on 
account of its characteristic tail. 
CRYPTONYMUS oOBTUsSUS, Ang., Pal. Scand., p. 3, plate 4, fig. 9. 
Cryptonymus obtusus, Vogd., Mong. genera Zethus, p. 22. 
Encrinurus obtusus, Pompecki, Tril., Fauna Westpreuss, p. 39, plate 5, 
figs, 25, 25-a. 
—Wigand, Zeitschr. Deutsch. Geol. Ges. 1888, p. 92, plate 10, fig. 24. 
This species was described from a tail and part of the thorax from 
Reg. E, Gotland. 
The pygidium is triangular; axis with 12 joints, notched at the sides, 
with a row of central nodes; pleurae 10. 
Pompecki, plate 5, figs. 25 and 25-a, show 14 joints, with 10 pleurae. 
The anterior border of the hypostoma is very much produced in the 
species (see Limdstrom Visual Org. Tril., plate 4, fig. 15.) Plate 3, fig. r4. 
ENCRINURUS RARICOSTATUS, Walcott, Adv. sheets 31st Rep. N. Y. State 
Mus., p. 16, 1877; p. 69 of the report, 1879. 
Encrinurus raricostatus, Safford & Vogdes, Proc. Acad. Nat. Sci., Phila., 1887, 
p. 167, fig. in text. 
Cryptonymus raricostatus, Vogdes, Mon. genera Zethus, &c., p. 27. 
Encrinurus raricostatus, Clarke, Geol. Minnesota, vol. 3, p. 740. 
Pygidium subtriangular, convex; length and breadth about equal. 
Axial not very prominent, with 16 joints. Pleurae 6. 
A similar species from the Trenton Limestone of Wisconsin was 
described by Clarke, Geol. Minnesota, vol. 3, p. 739, as Encrin. vannulus. 
The author illustrated the head, thorax in part, and pygidium. ‘The 
axis of the tail has 14 or 16 joints, with the first 6 or 7 joints extending 
across it; the others are notched at the sides. Pleurae 6. 
CRYPTONYMUS LAEVIS, Angelin, Pal. Scand. p. 4, Plate IV, fig. 10, Reg’ 
E. Gotland. 
—Vogdes, Mong. genera Zethus, &c., p. 22, plate 2, fig. 10. 
—Wigand, Zeitschr. Deutsch. Geol. Ges., 1888, p. 92, plate 10, fig. 25. 
The author figures an entire specimen. The genal angles of the 
head are rounded, and the surface coarsely tuberculated. Thorax, 11 
segments. Pygidium triangular, with 7 smooth pleurae; axial joints 14, 
notched at the sides; centre smooth. 
The hypostoma has its anterior margin prolonged, which character- 
istic marks the species. (Lindstrom Visual Org. Tril., plate 4, fig. 16). 
See plate 3, fig. 16. 
ENCRINURUS BOWNINGI, Foerste, Bull. Denison Univ., vol. 3, plate 22. 
The author illustrates the glabella only, which he compares with 
E. Barrandei, DeKon. 
