PLATE V. 



,,|, ;s PAGE. 



Olenus truncatus (Brunnich). 52 



1-3. Swedish specimens. 1, nearly complete; 2, head; 3, free cheek. Olenus schists, 

 Andrarum, Scania. Collected by Dr. J. E. Marr. Sedgwick Museum. 



4-6. Some of Belt's specimens. Upper Maentwrog Beds, Dolgelly. British Museum, 17558 

 (fig. 4), I 7561 (fig. 5), I 7556 (fig. 6). (Belt Collection.) 



7. Tail. Lower Lingula Flags, Cae Gwernog, Mawddach Valley. Sedgwick Museum. 



Olenus gibDOSUS (Wahlenberg). 54 



8. Nearly complete specimen, showing the lateral spine on the margin of the tail. Lower 



Maentwrog Beds, Dolgelly. British Museum, I 7546. (Belt Collection.) 



9. Head and part of thorax. Lower Maentwrog Beds, Dolgelly. British Museum, I 7548. 



(Belt Collection.) 



10. Head. Lower Maentwrog Beds, Dolgelly. British Museum, 1 7538. (Belt Collection.) 



Olenus micrurus, Salter. 55 



11,12. Salter's types. Lower Lingula Flags, Trawsfynydd. Museum of Practical Geology, 

 8948. (Both specimens are on the same slab of rock, and both nre in the form of 

 external moulds. The figures are drawn from artificial casts of these moulds.) 



Olenus cataractes, Salter. 56 



13. Probably Salter's type. Lower Lingula Flags, Treflys, Criccieth. Museum of Practical 

 Ceology, 8946. 



1 k Complete but distorted specimen. Lower Lingula Flags, Caen-y-coed Quarry, Maentwrog. 

 Sedgwick Museum. (The counterpart of this specimen is in the Museum of Practical 

 Geology, 8879.) 



15. Specimen distorted by cleavage, apparently with long thoracic and pygidial spines. This 



appearance is due to wrinkling of the surface of the slate. Lower Lingula Flags, 

 Caen-y-coed Quarry, Maentwrog. Sedgwick Museum. 



16. Thorax and tail. Lower Lingula Flags, Trefgarn Bridge, Haverfordwest. Collected by 



Mr. V. M. Turnbull. Museum of Practical Geology, 22715. 



17. Specimen showing fourteen thoracic segments. Lower Lingula Flags, Trefgarn Bridge, 



Haverfordwest. Collected by Mr. V. M. Turnbull. Museum of Practical Geology, 

 22717. 



All the figures on this plate are drawn natural size. 



