PLATE III. 



CRETACEOUS SPECIES. 

 Fig. 



1 to 13. Argiope decemcostata, various specimens, illustrating a few varieties of this 



form. 1 



6. ,, ,, Interior of smaller valve, enlarged. 



7. „ „ „ larger valve, „ 



14, 15. Argiope decollata, (recent,) placed here merely to show that the internal 



arrangements are more simple in the fossil form. See 

 the woodcut, Part I, page 9. 2 



17 to 28. Terebrirostra lyra, a number of specimens, nat. size. 



27. ,, „ a portion of the interior of smaller valve, the loop is not 



known ; h shows the produced boss. 



25 and 28. ,, „ Sections of the beak, enlarged. 



29. Terebratella pectita, the largest British specimen, nat. size. 



30 to 33. „ „ different varieties, enlarged. 



34 to 42. ,, Menardi, various specimens and varieties, mostly enlarged. 



34 to 47. „ „ nat. size. 



40 a . „ „ Interior of large valve, enlarged. 



41. ,, „ „ smaller valve, „ 



42. ,, „ A French specimen from Mans, enlarged, placed here for 



the sake of comparisons. 



1 Since the description of our British Cretaceous Argiope had gone through the press, I received from Mr. Suess, of Vienna, 

 a most interesting communication on Argiope (Ter.) decemcostata of Rcemer, in which that accurate observer had discovered the 

 existence of a loop like that of Argiope cislellula, &c. However, none of my French, Belgian, or English specimens belonging 

 to the form I figure, and attributed by myself to A. decemcostata, preserve the loop, or exhibit the mesial septum to the extent 

 represented by Mr. Suess. It may be doubted whether these differences between my specimens and that of Mr. Suess are 

 specific, or only due to age and state of preservation. 



2 Prof. Forbes and Mr. Cuming having kindly given me specimens of the other three recent species of Argiope, I am able to 

 add some details respecting them, which are necessary for the illustration of the genus. 



Jrgiopc decollata. Argiope Neapolitana. 



I. Argiope cuneata (Risso), erroneously mentioned by me as a synonym with A. decollata, has only a single median septum; 



the lobes of the loop are free for one half their extent in the specimen examined, arid blend with the shell, as 

 we have noticed in some examples of A. decollata. 



II. Argiope Neapolitana (Scacchi), T. seminulum, Phil. In this form the same longitudinal septum exists, but the loop was 



imperfect in the specimens at my disposal. 



III. Argiope cistellula (J. Wood). In this species the same mesial septum coexists with a complete two-lobed loop, as repre- 



sented in A. Neapolitana. The animal is preserved, and differs only from the figure given at Part I, in having 

 two lobes instead of four. In justice to M. Philippi, I must state that his figure of the animal of A. decollata 

 is essentially correct; but it is so small, that it has been overlooked or misunderstood by all succeeding 

 writers. M. Philippi himself failed to discover the loop, and perceive the nature of the fringed arms which 

 he described and figured. 



