268 PROCEEDINGS OF THE 



PI. V., tigs. 4-6. — The shell in question possesses to a great 

 extent the characters of Orthis Michelini (Leveille), having the 

 outline of this species, and the surface of both valves entirely 

 covered with small, straight, short spines. The valves are in 

 apposition, but have been pressed quite flat, or nearly so. 



The chief point of interest lies in the presence of a Crinoid stem, 

 which has passed through one corner of both valves, projecting 

 beyond. It is difficult to determine the manner in which this 

 has been accomplished. Had accident forced the encrinite stem 

 through the valves, we should have expected to find the shell 

 fractured to a greater or less extent — but this is certainly not the 

 case — and a disarrangement of the surface. On the other hand, 

 we cannot suppose there is, in this case, an attempt at attachment 

 such as we now know took place in some Brachiopoda, otherwise 

 the stem of the Crinoid would have been united to the Orthis 

 either by some portion of the hinge, or the general surface of one 

 of the valves. 



Presuming this to be only an accidental occurrence, it is worthy 

 of illustration as showing one of the many facts which have to 

 be taken into account in dealing with the peculiarities of sup- 

 posed adherent Brachipods. 



Locality and Horizon. — Skateraw Quarry, near Dunbar, in shale 

 above the Skateraw limestone (Mr. J. Bennie). 



Explanation of Plate V. (tigs. 1 to 7). 



Fig. 1. — Chonetes, sp. — Another example of the shell represented 

 in Plate VI., figs, 4 and 5, exhibiting one of the forms of distor- 

 tion. Kidlaw Quarry, near Clifford, Haddingtonshire. 



F 1G . 2. — Interior of another specimen, with the area preserved. 

 Skateraw Quarry, near Dunbar; Lower Carb. limestone group. 



Fig. 3. — Lingula mytiloides (Sow.) — A group of four indi- 

 viduals, with the remains of radiating colour bands. Roof-shale 

 of "Smithy" coal, Chance Pit, Bo'ness coal-field. 



Figs. 4-6. — Three views of a small Orthis (near 0. Michelini, 

 Lev.), perforated by a small Crinoid stem. Skateraw Quarry, 

 near Dunbar. 



N.B. — The natural size of the fossils is shown by the indicators. 

 The originals of Plate V., figs. 1-6, and Plate VI., figs. 1-5, are in 

 the collection of the Geological Society of Scotland. Those of 

 Plate VI., figs. 6-8, are in the British Museum. 



