ASAPHUS. 49 



There are some good hypostomes from Dow Hill, showing the typical characters 

 of Isotelus, which probably belong to this species. The hypostomes have a straight 

 truncated front, very short anterior wings, behind which the lateral margins are 

 slightly excavated, and they end in a pair of large triangular pointed lobes nearly 

 as long as the rest of the hypostome, and separated by a dee}) rounded notch. 

 There is no distinct body marked off by furrows, but in front of the notch is a 

 depressed elliptical area, and near the shoulders of the lateral margins is a pair of 

 macula?. In a specimen from Balclatchie the posterior lobes and border are 

 striated. These hypostomes closely resemble the one figured by Schmidt 1 as 

 belonging to /.so/, remigium, Eichw., and the hypostome of A. gigas figured by 

 Clarke, op. cit, p. 706, fig. 8. 



Collections. — Mrs. Gray (f. M.) ; Museum of Practical Geology (f. M.) ; Edinburgh 

 Museum ; Woodwardian [Sedgwick] Museum. 



Horizon and Localities. — Balclatchie Group (Llandeilo) : Dow Hill; Ardmillan. 

 (?) Balclatchie Conglomerate. 



3. Asaphus, sp. ind. Plate VII, fig. 0. 



Uemarlcs. — In Mrs. Gray's collection there is an imperfect head-shield from 

 Minuntion which apparently belongs to the group of Asaphus typified by . I. 

 expansus, Dalm. The glabella is of an indistinctly pear-shaped form with a 

 decided independent convexity, being slightly more elevated towards the base, 

 where there is a median tubercle. The eyes are prominent and situated nearly 

 opposite the middle of the glabella, and their distance apart is approximately equal 

 to the length of the glabella. The free cheek is produced slightly backwards, but 

 the genal angle is not preserved. 



Ajfinith's. — The species which seem most nearly allied to it are A. tyrannus, 

 Murch., A. peltastes, Salt., and A. raniceps, Dalm., 3 but it is too fragmentary and 

 badly preserved to determine its precise specific relations. 



Dimensions. — 



Length of head .... 22'0 mm. 



Width „ (about) . . . 42-0 „ 



Width between eyes (about) . . . 21*0 „ 



Collection. — Mrs. Gray. 



Horizon and Locality. — Stinchar Limestone Group (Llandeilo) : Minuntion. 



1 Schmidt, ' Rev. Ostbalt. Silur. Trilob.,* Abth. v, pt. ii (1900), pi. x, fig. 17. Brogger, 'Hypost, 

 Asaph.,' p. 31 (Bih. t. k. Vet. Akad. Handl., vol. ii, No. 3, 1886). 



2 Dalman, ' Palaead.,' pi. iii, fig-. 4 (1827) ; and Schmidt, op. cit., p. 32, pi. i, figs. 8 — 11 ; pi. ii, 

 figs. 1—3. 



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