KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND. 19. N:0 6. 193 



The systematic place of the species of this fainily is by far not as easily cleared 

 up as their nature of siphonostomous shells and I think, that this question must for 

 the present be left undecided. 



Gen. 8UBULITES Conrad. 



1842 Sttbulites Conead Nat. Hist. of N. York, Geol. vol. II, 392, fig. 3. 



1843 Polypliemopsis Portlock, Eept. Geol. of Londonderry, 415. 



Shell slender^ elongate and fusiform. Whoiis straightly conical or ordy sUghtly con- 

 vex, suture shallow, and on hoth sides a nearly rectilinear outline is formed. Shell thin, 

 fragile and unadorned, last ivhorl elongated. Äperture elongate or more than double the 

 length against the breadth. It is narroio, the outer Up thin and its lowest corner proloji- 

 ged into a small acuminated hooJc, lohich is most characteristic. The inner Up is involute, 

 thus forming a central canal around the axis, and it ends above abruptly in a transverse 

 line, from ichich the apertural edge continues in a rounded arch. They have a tendency 

 to grow obliquely along a curved axis. 



On plate XVIII a sketch of the apertiire of the recent, siphonostomous Daphnella 

 limnaaiformis L. has been given, fig. 64, to compare with that of Subulites ventricosus, 

 figs. 58 & 59, and of Subiil. curvus fig. 61. The great accordance, especially between 

 fig. 64 and fig. 59, is striking. In all there is almost the same form of the äperture, on 

 the columellar side the same narrow coating of a thin porcellanous stratum, and, above 

 all, uppermost the peculiar and characteristic notch which indicates where the sipho 

 is protruded in the recent shells and probably also had been protruded in the extinct 

 ones. Ås far as this evidence goes, there is every reason to conclude that Subulites, 

 as well as the related genera, also have been siphonostomous. The transverse sections 

 of Subulites and Euchrysalis, figs. 62 & 68, show the inflected columellar lip in the 

 same rnanner as a similar section of Daphnella, fig. 63, while the section of a holosto- 

 mous, recent Turritella, fig. 69, is quite different. 



The oldest specimens of this genus already occur in the Lepttena Limestone of 

 Dalecarlia. In the »Fragmenta Silurica»') I have with some hesitation descinbed a 

 species as Subulites elongatus Portlock, but 1 now thihk that it is identical with Heli- 

 cites utricularis Wahlenberg^) and that it thence is to be named Sub. utricularis. This 

 genus seems to be restricted exclusively to the Silurian formation. 



1. Subulites ventricosus Hall. 



Pl. XV fig. 19—21, tab. XVIII fig. 58—59. 



Subulites ventvicosa 1852. Hall Pal. N. York, II, 347, pl. 83 f. 7. 



1865. Id. 20th Rept. N. Y. St. Cab., 346, pl. 15 f. 1. 



1) Pag. 13, pl. XV f. 21—23. 

 -) Petref. Suec. p. 72. 



K. Sv. Vet. Akad. Ha.idl. Bd. 1!) \;o C. 



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