190 CRETACEOUS GASTROPODA 
and the aperture is oval or nearly circular and somewhat dissolute from the last volu- 
tion. In full grown specimens the anterior canal is distinct, but it is almost tubular, 
likein Zriphoris, and communicates with the apertural space only by a very narrow 
hole. When the canal is accidentally broken away, it is very difficult indeed to 
resume its former existence, and the aperture then appears to have had continuous 
margins. Taking into consideration, that of all the species which have as yet been 
described as Hveliss@, not one has been recorded with a really perfect aperture, 
and that nearly all of them are known from small specimens only, it should not 
surprise us, when ashort anterior, and, as I have stated, rather a tubular canal may be 
proved to exist. It is of course merely a conjecture for the present, for we cannot 
give any decisive opinion whatever on the subject. But if there were really no 
trace of an anterior canal present in Hvelissa, the genus ought necessarily to be 
transferred to the Scazarup#, with which the posteriorly united margin of the 
aperture otherwise agrees. e 
There is a large variety of jurassic species of czrzrazzy“ known, which will most 
probably suggest several new generic names, as for instance the many-whorled 
species resembling Turritella, but with a distinct anterior canal; others with numerous 
angular whorls and somewhat of a more cylindrical shape, like some species of 
Colina, but with only a very shallow canal and expanded inner lip, similar to 
Eustoma, and others. We abstain here from any further remarks, for it is to be 
expected that all these forms will receive proper attention at the hands of 
M. Piette, who has undertaken the continuation of the jurassic Gastropoda in 
D’Orbigny’s ‘ Paléontologie frangaise.’ 
There is a large number of cretaceous species, which are distinguished by 
their conical form and flattened volutions, resembling Hlenchus or Bankivia of the 
Trocurpz. They have a short contorted canal and apparently a very thin outer lip. 
‘But as we are not in possession of any complete specimens,we are contented to direct 
attention to this group of Cerithiwm, although it is very likely that they must be 
generically distinguished from others. As typical forms we would quote Cer. orna- 
vissimum, D’Orb., C. Mosense, Buvignier, C. Cogandi, Pict. et Camp.; Cer. fertile, 
n. sp., and other similar forms. 
7. Sandbergeria, Bosquet, 1860, has been proposed for a number of tertiary, 
ovate species, which have a very broad, shallow, but slightly prolonged canalicu- 
lation in front. If the paucispiral operculum, to which Mr. Bosquet refers, really 
belongs to species of this genus, it can be justly retained. Deshayes (Paris foss. 
2d. edit., Vol. III, p. 112) is of opinion that, although belonging to a very marked — 
section of Cerithiwm, the characters are not sufficient to justify a separate genus. 
If these shells belong to the czrzruizv2, that is, if the paucispiral operculum is a 
genuine one, they ought to be generically separated from Cerithiwm, but if it can be 
proved that the operculum was circular and multispiral, it would be very difficult to 
draw a line between Sandbergeria and Cerithidea, and perhaps Mesalia of the 
Torrirattipe. With regard to Cerithidea there is only one point which deserves 
attention. Looking upon the recent species of this genus it may be seen, that the 
