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



The systematic place of the species of this family 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. SUBULITES Conrad. 



1842 Subidites Conrad Nat. Hist, of X. York, Gcol. vol. II, 392, fig. 3. 



1843 Polyphemopsis Portlock, Eept. Geo), of Londonderry, 415. 



Shell slender^ elongate and fusiform. ]Vho)i$ straightli/ conical or only slightly con- 

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

 fragile and unadorned, last whorl elongated. Aperture elongate or more than double the 

 length against the breadth. It is narroiv, the outer lip thin and its loivest corner prolon- 

 ged into a small acuminated hook, ichich is most characteristic. The inner Up is involute, 

 thus forming a centred 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 aperture of the recent, siphonostomous Daphnella 

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

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

 fio-. 64 and fig. 59, is striking. In all there is almost the same form of the aperture, 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. As 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 manner 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 Leptsena Limestone of 

 Dalecarlia. In the wFragmenta Silurica»') I have Avith some hesitation described a 

 species as Subulites elongatus Portlock, but I now think that it is identical with Heli- 

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

 irenus seems to be restricted exclusively to the Silurian formation. 



1. Subulites ventricosus Hall. 



PI. XV fig. 19—21, tab. XVIII ficr. .58—59. 



Subulites ventricosa 1852. H.\ll Pal. N. York, II. 347, pi. 83 f. 7. 



1865. Id. 20th Kept. N. Y. St. Cab., 346, pi. 15 f. 1. 



1) Pag. 13, pi. XV f. 21—23. 

 -) Peti-ef. Suec. p. 72. 



K. Sv. Vet. Ak.ii Ua.Tll. Bd. V.< X;n i: 10 



