Descrij)tion of Genera and Species. 59 



been no provision for articulated spines along its outer margin. The inner branch is 

 much smaller and of more delicate construction. Near its base, which is slightly 

 swollen, there is an oval ring within which there is a smooth saucer-like depression, in 

 the centre of which there rises an inner, much smaller oval ring, or rather flat boss. 

 As the structure has been found occupying this position in all the tails examined and 

 on both sides of the telson, there is left no room for doubt as to its representing the 

 auditory organ similarly situated in the tails of the receiit Mysid«. The portion of 

 the uropod which projects beyond this organ is weak and tliiu, linguate in form, and 

 set round with fine setai, and does not extend beyond the end of the telson. The 

 whole tail fan when expanded is deeply forked or swallow-tailed. The species is 

 named after Mr. Robert Dunlop, to whom I feel deeply indebted for haviTig placed his 

 collection of tails at m}' disposal for study. 



Locality. — Greengairs, 3|- miles N.N.E. from Airdrie, Lanarkshire. 



Horizon. — Soft Band Ironstone, Lower Coal Measures, '• Lanarkian." 



Collectors. — E. Dunlop and D. Tait. 



Pal^emysis couttsi sp. nov. PI. VIIL, figs. 16-19. 



Specific Characters. — Only the last few tail segments known ; sixth segment 

 relatively longer and narrower than in P. dunlopi ; telson relatively shorter and more 

 deeply notched ; the blade-like external branch of the uropods relatively longer than 

 the internal one, so that the tail fan is deeply swallow-tailed when expanded. 



General Description. — This name is proposed for a species which, to judge from 

 the last segment and the attached tail fan shown natural size, is seen to be nearly 

 allied to P. dunlopi just described. From that form it differs in its much greater size 

 and more elongated and elegant proportions, especially of the last tail segment. The 

 telson is relatively shorter and more deeply forked, and the external branch of the 

 uropod, which is of the same blade-like character, is relatively much longer than the 

 telson, and the inner branch is also longer than the telson. The auditory organs have 

 not been observed, although they no douljt occur. 



Remarks. — The specimens from which the drawings were made were submitted to 

 me by the late Mr. Coutts of Glasgow. They are now in the Natural History 

 Collection of the Eoyal Scottish Museum, Edinburgh. By the kind permission of Dr. 

 Dobbie, the Director, I now make use of my drawings for this description. 



Locality. — Cementstone Quarry, East Kilbride, Lanarkshire. 



Horizon. — Lower Limestones, Scottish Carboniferous Limestone Series. 



Collector. — And. Patton. 



