GEOLOGICAL SURVEY IN SILURIAN ROCKS OF SOUTH OF SCOTLAND. 863 



Lanarliia spinosa, Traq. 



Fig. 7. Entire specimen, somewhat distorted on right side ; natural size. Downtonian, Seggholm. 



Fig. 8. Another entire specimen from the same horizon and locality ; natural size. 



Fig. 9. Portion of integument from a specimen from Birkenhead Burn, magnified, showing the larger 

 dermal spines intermixed with those of minute size ; magnified nine diameters. 



Figs. 10-12. Three of the larger dermal spines also from a Birkenhead Burn specimen, magnified twelve 

 diameters. 



Plate IV. 



Lanarlda spinosa, Traq. 



Fig. 1. A small specimen from Seggholm, in which the larger spines are very strongly marked. 

 Enlarged one half. 



Fig. 2, Portion of integument of the same specimen, magnified four diameters. 



Lanarliia spinulosa, Traq. 



Fig. 3. Imperfect specimen from the Downtonian horizon, Birkenhead Burn ; natural size. 



Fig. 4. Spiny integument of the same specimen, magnified six diameters. 



Fig. 5. Isolated dermal spine from another specimen, magnified twenty diameters. 



Ateleaspis tessellata, Traq. 



Fig. 6. Specimen from the Downtonian horizon, Seggholm, fairly complete in front, but obliquely cut 

 off behind. 



Fig. 7. Portion of the body of another specimen ; natural size. 



Fig. 8. Upper lobe of the caudal fin of another specimen ; natural size. 



Fig. 9. Tesserae of the surface of the head, seen in impression on the counterpart of the specimen 

 represented in fig. 6, and magnified five diameters. 



Fig. 10. A squeeze in modelling wax taken from a similar part, also magnified five times. 



Fig. 11. Scales from behind the head of the specimen shown in fig. 6 as seen in a squeeze in modelling 

 wax taken from the counterpart, magnified three diameters. 



Fig. 12. Scales from specimen shown in fig. 7, magnified two diameters. 



All these specimens of Ateleaspis are from the Downtonian Beds of Seggholm. 



Plate V. 



Birkenia elegans, Traq. 



Fig. 1. Entire specimen from Birkenhead Burn (Downtonian), enlarged one half. 

 Fig. 2. Another specimen from the same locality, having the body shortened up, enlarged one half. 

 Fig. 3. Head of another specimen from the same locality, enlarged one half. 



* ig. 4. Impression of a detached scute of the median ventral series, magnified four diameters. From 

 Lyneslie Burn, Pentland Hills. 



Lasanius problematicus, Traq. 



rig. 5. A specimen from Birkenhead Burn, showing the fish as it usually occurs — the ventral scutes 



and the gridiron-like arrangement of rods being in position with regard to each other. Enlarged by one 

 half. 



VOL. XXXIX. PART III. (NO. 32). 6 R 



