176 Proceedings of the Boyal Physical Society. 



Log. and Horizon. — Drummuck, near Girvan, in rocks 

 of Llandeilo age, according to the map of the Geological 

 Survey of Scotland, 



2^ot(>, — In addition to the fossils here described, there were 

 exhibited at the meeting of the Eoyal Physical Society, at 

 which the paper was read, the following : 



1. Trinncleus, sp. — A fine form nearly allied to, but distinct 

 from, T. BucMandi, Barr. (Syst. Sil. Boheme, 1852, i., p. 621. 

 Atlas, p. 629, f. 10-17.) Drummuck, near Girvan. 



2. Trinncleus, sp. — Closely allied to, if not identical with, 

 T. seticornis, His. Drummuck, near Girvan. 



3. Lingida Canadensis, Billings. Balcletchie, near Girvan. 



4. Lingida quadrata, Eichwald. 



5. Siphonotreta Scotica, Davidson. Craighead, near Girvan. 



6. Strophomena corrugatella, Davidson. Balcletchie, near 

 Girvan. 



(Nos. 3, 4, and 5 have lately been described by Mr T. 

 Davidson, F.K.S., as new to British Silurian rocks, from speci- 

 mens obtained by Mrs Gray at the localities mentioned.) 



I have, in conclusion, to express my thanks to Mrs Eobert 

 Gray for her kindness in giving me access to the valuable 

 contents of her cabinet. 



Explanation of the Plate. 



Fig. 1. Turrilepas Scotica, R. Etli., jun. — Twice the natural size, show- 

 ing the finely drawn out superior end. Balcletchie. 



Fiw. 2. Another specimen, nearly twice enlarged. Balcletchie. 



Fig. 3. Pinnocaris LapivortU, R. Eth., jun.— Natural size, showing the 

 rounded larger end of one-half the carapace, the attenuated and truncated 

 end, and the tail spine (?) displaced. Balcletchie. 



Fig. 4. Another specimen of the same, natural size, showing the false umbo 

 and two halves of the carapace in apposition. Balcletchie. 



Fio-. 5. A third example of the same, natural size, showing one-half of the 

 carapace slightly displaced from the other half, at the attenuated end, and 

 the concentric strise, Balcletchie. 



Fig. 6. Acidaspis Graycc, R. Eth., jun.— A mould about twice the natural 

 size, with the head, thorax, and pygidium, so far as preserved, united 

 together. Around the frontal margin of the head may he seen the non- 

 denticulated spines, whilst those i)rojecting from the pleuree of the thorax 

 are so. 



Fig. 7. Another pygidium and a few thoracic somites of the same, some- 



