28 TRILOBITES OF GIRVAN. 



Remarks. — This small trilobite is only represented by one specimen, measuring- 

 only about 6'5 mm. in length, which is in Mrs. Gray's collection, and it is of 

 special interest as being the earliest example of the genus in the Girvan area. It 

 appears to be allied to Cyphaspis matutina, Ruedemann,^ of the Trenton Formation, 

 and to 0. parvula, Pompecki,^ from Konigsberg. 



Horizon and Locality. — Balclatchie Group (Llandeilo) : Balclatchie. 



Family Lichadid^. 



Genus LICHAS, Dalman. 



Lichas (Corydocephalus) maccullochi, sp. nov. Plate IV, figs. 9, 10. 



Specific Characters. — Head-shield transversely semi-circular. Cranidium 

 strongly convex-, arched down anteriorly, projecting in front of free cheeks. Gla- 

 bella and fixed cheeks equally swollen. Median lobe of glabella clavate, projecting 

 in front of lateral bi-composite lobes, completely embracing their front ends with 

 narrow recurved over-hanging lateral extensions; posterior three-fourths of median 

 lobe parallel-sided, cylindrical, crossed at base of bi-composite lobes by transverse 

 furrow strongly arched back, separating oif posterior fifth part as post-median 

 lobe. Bi-composite lateral lobes sub-oval, completely circumscribed, about one and 

 a half times as long as broad, with axes parallel and with faint notch indenting 

 inner sides behind middle. Fourth lateral lobes completely fused with fixed cheeks, 

 forming transverse swollen cushion rising steeply from depressed neck-ring. 

 First lateral furrows curve forwards in front of bi-composite lobes, thence run back 

 parallel or subparallel to base of latter, where they end in deep pits connected 

 across median lobe by transverse furrow. Post-median lobe bounded laterally by 

 shallow parallel grooves continued back from these pits to occipital furrow. 

 Second lateral furrows nearly at right angles to axial furrows and to first lateral 

 furrows, defining the bi-composite lobes behind. Axial furrows only present in 

 front of second lateral furrows, completely undeveloped behind them. Meso- 

 occipital ring simple, rounded, broad in middle behind post-median lobe of glabella, 

 narrowed on each side, with occipital lobes forming small subcircular swellings partly 

 fused with posterior slopes of fourth lateral lobes. Pleuro-occipital ring narrow. 



Free cheeks triangular, with genal angle produced broadly back to fourth or 

 fifth thoracic segment, and pointed. Eyes small, prominent, situated just behind 

 level of second lateral furrows, and distant from sides of median lobe rather more 

 than one and a half times its width. Surface of glabella and cheeks covered with 

 fine granulations and a few scattered tubercles. 



» Euedemann, ' Bull. 49 New York State Mus.,' Pateout. Papers 2 (1901), p. 62, pi. iv, figs. 5—7. 

 - Pompecki, ' Trilob. ost.-westpreuss. Diluv. Gescliiebe ' (1890), p. 57, pi. vi, figs. 28, 28 a. 



