STROPHALOSIA. 39 



English Strophahsias at present known into four or five species, 1 while others would feel 

 disposed to admit but two or three. Assuming, therefore, that the Strophahsias in 

 question belong but to two species, and that these are properly identified as the Stropha- 

 losia Goldfussi, Minister, and S. lamettosa, Geinitz, there exists, in my opinion, two or 

 three varieties deserving a special notice, as well as a varietal designation. I have there- 

 fore described these separately, and given the different opinions entertained, in order that 

 the reader may have a better opportunity of judging for himself as to the grounds upon 

 which a larger number of species have been maintained, as the subject may still afford 

 grounds for further discussion. 



Strophalosia Goldfussi, Munster. Plate III, figs. 1 — 10. 



Spondylus Goldfussi, Munster. Beitrage, vol. i, p. 43, pi. iv, fig. 3 a, b, 1839. 

 Orthis excavata, Geinitz. Neues Jahrback for 1842, pi. x, p. 578, figs. 13, 14. 

 Productus Goldfussi, Be Koninck. Monographe du genre Productus, p. 148, pi. xi, 



fig. 4 ; and pi. xv, fig. 4, 1846. 

 Orthotrix Goldfussi, Geinitz. Versteinerungen, pi. v, figs. 27, 28, April, 1848. 

 Strophalosia Goldfussi, King. Monograph, p. 96, pi. xii, figs. 1 — 12, and 23? 



1850. 



— parva? King. Mon., p. 102, pi. xii, fig. 33, 1850. 



— Goldfussi, Hawse. Annals and Mag. of Nat. Hist., vol. xix, 2d series, 



p. 47, 1857. 



Very variable in its external shape, generally more or less sub-triangular (figs. 5, 7), sub- 

 quadrate (fig. 6) or oval, but less commonly circular ; its anterior angles are rounded, 2 and 

 at times slightly indented in front. The hinge-line is always much shorter than the width 

 of the shell ; the beak of the larger valve tapering a little, and often twisted more to the one 

 than to the other side ; area narrow (figs. 1, 6, 14), with the extremity of the beak slightly 

 protruding beyond its extremity, or large, triangular, and more or less bent backwards 

 (figs. 3, 5, 8), varying both in height and breadth, with a narrow fissure covered by a 



1 Professor King writes me on the 29th of July, 1857 — "My present view of Permian North of 

 England Strophalosias is, that there are the following species : S. excavata, S. Goldfussi, S. Humbleto- 

 nensis, S. Morrisiana, and (!) S. parva. I doubt much that Orthotrix lamellosa and Cancrini of 

 Geinitz and Germany are the same as my Morrisiana and Humbletonensis. The lamellosa does not appear 

 to occur in the North of England." 



2 Professor King alludes to the great variability presented by the different individuals composing the 

 present species. At p. 97 of his Monograph, he also mentions that the casts so abundant at Ryhope-field 

 House differ from those found at Humbleton hill, in having the larger valve more rounded, with a very 

 small indication in some specimens of a median furrow. This fact has also been confirmed by Messrs. 

 Howse and Kirkby, who have assembled a vast number of specimens from both localities. The length, of 

 the hinge-line is often not more than one third of the breadth of the shell. There appears also to exist 

 every passage from those examples which are longer or shorter than wide to those which are almost circular; 

 some are irregularly and scantily spined, while others have the spines closely and regularly placed. 



