KONGL. SV. VET. AKADKMIENS HANDLINGAR. BAND. 19. N:0 6. 41 



ample material to work upon, these peculiarities in structure may serve to subdivicle 

 the Conularia3 in narrower circumscribed subgenera, as there are concomitant charac- 

 ters, for instance in the ornamentation. 



As to the peculiar diaphragmas, which have been observed in so many ConularioB 

 near the apes, in sorne species one, in others several, there is nothing in this feature 

 that is discordant with the interiör structure of the Pteropods, in so many respects 

 aberrant from the other Mollusca. In the genus Triptera Quoy & Gaymard (Cuvieria 

 Rang) ^) there is a diaphi-agma or entire transverse septum near the apex, dividing the 

 shell into one large chamber, where the animal is lodged, and one smaller, forming 

 the empty tip and often deciduous, quite as it has been the case with Conularia, where 

 the apex is gone below the septum. In consequence of what now has been stated, this 

 genus Conularia may be left amongst the Pteropods, until some positive and decisive 

 facts have been adduced, causing its removal into another systematic place. 



There is, however, a species, C. fecunda, described by Barrande in his Syst. 

 Silur. de Bohéme, vol. III p. 38, which has an exceptionally thick and heavy shell, of 

 many superimposed layers of shelly matter. Such a fossil may throw doubt on the 

 Pteropodan nature of the whole genus. This species links another curious fossil. Te- 

 tradium Fr. Schmidt, non Dana ^), with the Conulariaj and makes it probable that it 

 may stånd in some affinity to them, though it not, as has been supposed, is likely to 

 have been the operculum of some Conularia. It is quite as heavy and compact as C. 

 fecunda and the anterior aperture has the side corners prolonged into hornlike spines. 

 As to the interiör tubular structure as shown by Schmidt in his fig. 8, and which 

 according to him also is seen in Conularia, it may probably be derived from some 

 parasitic fungus, as so often is the case and also may be seen further down in Tryblidium. 

 In the specimens of Conularia, which I have exarained, I have not hitherto found any- 

 thing at all analogous. 



In Sweden the Conularias make their first appearance in the Upper gray Ortho- 

 ceratite limestone of the isle of Oland with a species, which is scarcely discernible from 

 the låter, which occur in the Chasmops limestone of Boda on Öland, in the younger 

 Retiolites shale of Borenshult in Östergötland and, as it now seems likely, also in the 

 Upper Silurian strata of Gotland under the name of C. cancellata Sandb. 



Of this genus there are found in Gotland five species of which three are compa- 

 ratively coramon, but of the two others only one specimen to each is known. 



These species may be arranged in the following groups. 

 * Ornamental ribs thick with closely set tubercles. 



1. C. cancellata Sandberger. 



2. C. monile n. 



') Description de deux genres nonveaux nppnvtenaiit ;\ la classe des Ptéropodes, Ann. So. Nat. Torne XII 



p. .324. 

 ^) ScHMiuT Miscellanea Silurica II. in Mém. de TAcad. Se. de St. Petersbourg VII Ser. Torne XXI. N:o 



11 p. 42. 



K. .Sv. Vet. Akad. Haaill. Bd. 19. N:o (i. 6 



