Mr. T. C. Eyton on apeculiar Ischiatic Process in Erucivorcs, 457 



Plate XV. 



Fig. 1. Narrow furrowed track of Krbyera arenaria: a, furrow; b>b, slight 



lateral ridges. 

 Fig. 2. Variety of ditto, regularly zigzagged. 



Fig. 3. Track exhibiting a rounded ridge, a, with a narrow lateral furrow, b. 

 Fig, 4. Ditto, with the ridge broken up into nodules : a, groove. 



Plate XVI. 



Reduced view of a slab, bearing nodulous tracks, in the possession of Mr. 

 Wood : a, a, nodules ; b> b, points where one fold or winding 

 cuts through another. 



Plate XVII. 



Fig. 1. View of a slab exhibiting nodulous tracks, with the cast of the 

 burrow partially removed : a, a, portions of the tracks with the 

 cast removed, showing impressions of the nodules ; b, ditto, 

 ditto, showing one track passing through another ; c, c, supposed 

 sinkings or perforations of small crustaceans ; d, a small track 

 terminating in similar perforations, e, e; f,f f septa dividing the 

 nodules. 



Fig. 2. Side view of a portion of the cast of the same track, showing the 

 nodules, a. 



Plate XVIII. 



Reduced view of a slab in the Newcastle Museum, exhibiting tracks: 

 a, large, depressed, grooved track ; b, groove of ditto ; c,c,c y small 

 furrowed tracks passing over the large grooved species in various 

 directions. 



Plate XIX. 



Fig. 1. View of a slab, of the natural size, in the possession of Mr. Howse, 

 bearing a small, much-convoluted variety of the large grooved 

 track : a, central ridge. 



Fig. 2. Portions of a variety of large grooved track, of the size of nature, 

 showing a central elevated area and transverse striae or ridges : 

 a, central elevated area ; b, central groove of ditto ; c, c, lateral 

 areas ; d, portion of another track, exhibiting the central ele- 

 vated area broken up into nodules, e, e. 



XLIX.— Notes on Birds. By T. C. Eyton, Esq., F.L.S. &c. 



[Continued from vol. xvii. p. 313, 1st series.] 



No. VII. On a peculiar Process attached to the Ischium in 

 Erucivores. 



It is now some time since, in my own collection, I separated 

 the Cuckoos from other Scansores under the above name, which 

 was first proposed at the Meeting of the British Association 

 lately held at Leeds ; but it was only a few days ago that I dis- 



