BRITISH FOSSILS. 



7 



I cannot reconcile the Galerites glohosus and Galerites elongatus of 



F. A. Romer (" Versteinerungen des Norddeutchen Kreidegebirges," 

 PI. VI., figs. 14 and 15) with any of the above. The figures are, however, 

 very bad, and it is not improbable that the former may prove identical 

 with the nucleus variety of suhrotiindus, and the latter with some form 

 of ahhreviatus. 



A fifth species of true Galerites^ but one not hitherto found in Britain, 

 is the G. suhsplicBroidalis of D'Archiac, described and figured in that 

 geologist's excellent account of the fossils of the Tourtia. It is allied to 



G. subrotundus, but is perfectly distinct, and should be sought for in the 

 upper beds of the English lower green-sand, where many Tourtia fossils 

 occur. 



Localities and Geological Position. — This species is found distributed 

 throughout the white chalk of the English cretaceous districts. It is 

 very abundant in the south. Very fine specimens are found in Kent, as 

 at Gravesend, &c. Examples with spines are contained in the Museum 

 of the Geological Survey, and in Mr. Bowerbank's collection. Specimens 

 showing the teeth are in the collections of Mr. Stokes and Mr. Bowerbank. 

 Some interesting forms have been presented to the Survey by Mr. 

 Wetherell. 



Foreign Localities. — White chalk of France, Germany, and Belgium, 

 apparently not universally diffused through the spread of this formation. 



Description of the Plate, 



Fig. 1. Profile of the most common variety. 

 Fig. 2. The same seen from below. 



Fig. 3. Outline (lateral view) of an extremely pyramidal specimen. 

 Fig. 4. Outline (lateral view) of an extremely depressed and tumid variety. 

 Fig. 5. Ambulacra! and interambulacral plates, pores, and tubercles, taken from the 

 centre of the sides. 



Fig. 6. Arrangement of pores and tubercles in the neighbourhood of the mouth. 

 Fig. 7. Spiniferous tubercles and miliary granules taken from the base. 

 Fig. 8. Greatly magnified figures of the small tubercular spines of the dorso-lateral 

 plates. 



Fig. 9. a. One of the spines of the lower surface highly magnified, c. Its section. 

 d. Pedicellaria-like body, intermixed with the spines. 6. Portion of spine of Galerites 

 suhrotundus for comparison. 



Fig. 10. Masticatory apparatus, natural size. a. The same seen from one side, highly 

 magnified, b. One of the teeth seen in profile. 



Fig. 11. Diagram of the supports of the masticatory apparatus around the inner rim 

 of the mouth. 



Fig.-12. Apical disk; genital and ocular plates. 



