part 2] GEOLOGICAL HISTORY OP THE GENUS STRATIOTES. 133 



1893. P. carinatus Nehring (Clement Eeid 49). 



1894. F. carinatus (Nehring-) Potonie (Potonie 50). 



1895. F. carinatus (Nehring-) Potonie (Nehring 51). 



1895. F. carinatus (Nehring) Potonie (Nehring 52). 



1896. F. carinatus Nehring (Gr. Andersson 53). 

 1896. Stratiotes aloides Linn. (Keilhack 54). 

 1896. 8. aloides Linn. (Nehring 55). 



1896. 8. aloides Linn. (Keilhack 56). 

 1896. S. aloides Linn. (Nehring 57). 

 1897-99. S. aloides Linn. (Potonie' 58). 

 1899. 8. aloides Linn. (Clement Eeid 59). 

 1905. ? S. ivebsteri Potonie (Eugene Dubois 61). 

 1906-07. 8. aloides Linn. (Schroder & Stoller 63). 



1907. 8. aloides Linn. (C. & E. M. Eeid 64). 



1908. ? 8. ivebsteri Potonie (Engelhardt & Kinkelin 65). 



1908. S. aloides Linn. (C. & E. M. Eeid 66). 



1909. S.. aloides Linn. (Hartz 67). 

 1911. S. aloides Linn. (Krause 69). 

 1920. S. aloides Linn. (Menzel 72). 



The description already given of the recent S. aloides holds 

 good for the fossil species (see p. 118). In one particular only is 

 there ever any difference worthy of remark. The testa of the 

 recent S. aloides is invariably smooth or ornamented with very 

 obscure ridges, and this is frequently true also of the fossil 

 S. aloides ; but, in addition to the smooth forms, there are other 

 rougher ones associated with them, and in a series of fossils from 

 a given locality it is often possible to trace every gradation 

 between the rougher and the smoother forms. It is impossible to 

 place a dividing-line between the two types, and to aver that here 

 one species or variety ends and another begins (see p. 122). 



Dimensions. — Length = 7 "2 to 9 mm. ; breadth = 2 to 3 mm. 



Horizons. — Upper Pliocene, Pleistocene. 



Localities, — Tegelen-sur-Meuse near Venloo (Limburg), 

 Upper Pliocene (Teglian of Reid) ; Cromer Forest-Bed (Beeston, 

 Pakefield, Sidestrand, and Corton), Upper Pliocene (Cromerian 

 of Reid) ; South Elmham (Suffolk) (Interglacial of Reid) ; peat- 

 beds of Klinge near Cottbus (Interglacial of Nehring) ; Jutland 

 (Interglacial of Hartz). 



Affinities. — A very close relationship exists between S. aloides 

 and the Preglacial S. intermedins. The latter differs only in 

 being a larger, stouter form, having a crested keel, also more pro- 

 nounced and more numerous tubercles. 



IX. Bibliography. 



(1) 1810. Annales du Museum d'Histoire Naturelle de Paris, vol. xv, p. 382, 



& pi. xxxiii, fig. 17. Alexandre Beongniaet. 



(2) 1822. ' Description Geologiquc des Environs de Paris ' pp. 62, 289, 295, 366, 



pi. xi, fi<;s. 4-5. G. Cuviee & Adolphe Brongniart. 



(3) 1822. ' Classification des Vegetaux Fossiles ' M(5m. Museum Hist. Nat. Paris, 



vol. viii, p. 317. Ad. Brongniaet. 



(4) 1825. 'Versuch einer Geognostisch-Botanischen Darstellung der Flora der 



Vorwelt' vol. i, fasc. 4, p. xli, & pi. liii, fig. 8. K. von Stern- 

 berg. 



(5) 1825. ' Botanische Bemerkungen iiber Stratiotes & Sagittaria ' pi. i. 



E. F. Nolte. 



Q. J. G. S. No. 314. l 



