PLATE XVII. 



UPPER SILURIAN CRUSTACEA. 



Order — Merostomata. 

 Sub- Order — Eurypterida. 



Figs. 1 — 4. — Slimonia acuminata, Salter, sp. P. 105. 



Fig. 



1. This is by no means the largest, but it is one of the most perfect, specimens met 



with by Mr. Robert Slimon at Lesmahagow. Both the intaglio and relievo are 

 now preserved in the British Museum. 



The specimen exhibits its ventral aspect. 



The small letters and figures refer to the same parts and organs as indicated in 

 Parts I & II of this Monograph. 



2. A detached thoracic plate, exhibiting the tricuspid termination of the median lobe (c). 



From a specimen in the British Museum. P. 114. 



3. One of the antenna?, with its serrated basal joint, and also that of the opposing 



maxilla. P. 109. 



4. One of the endognaths. The mandible in this specimen is turned the reverse way. 



P. 111. 



All drawn of the natural size from specimens in the British Museum. 

 Formation. — Uppermost Ludlow Rock. 

 Locality. — Lesmahagow, Lanarkshire. 



