Mr. T. C. Eyton on a peculiar Ischiaik Process in Emcivorcs. 457 



Plate XV. 



Fig. 1. Narrow furrowed track oi Kroyera arenaria: a, furrow; b,b, slight 



lateral ridges. 

 Fif/. 2. Variety of ditto, regularly zigzagged. 



Fig. 3. Track exhibiting a roimded ridge, a, with a nan'ow lateral furrow, b. 

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



Plate XVI. 



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

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

 cuts through another. 



Plate XVII. 



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

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

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

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

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

 terminating in similar perforations, e, e; 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 \-iew of a slab in the Newcastle Museum, exhibiting tracks : 

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

 fiuTowed 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, 

 bcaiing a small, much-convoluted variety of the lai'ge grooved 

 track : a, centi-al ridge. 



Fig. 2, Poi-tions of a variety of large grooved track, of the size of nature, 

 showing a central elevated area and transverse strios 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. 



XUX.— 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 owii collection, I separated 

 the Cuckoos fi'om other Scansores under the above name, which 

 was fii'st proposed at the Meeting of the British Association 

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



