ts f 
J. S. Gardner—Cretaceous Gasteropoda. 51 
ing towards the outer lip, the front one being the less prominent), 
and three smaller keels, which are arranged above, below, and 
between, the primary keels. All the keels seem to have been tuber- 
culated, and the spire was probably ribbed, as in T. Grifithsii, which 
it generally resembles. Length of fragment 22 mm., diameter of 
body-whorl 12 mm. 
This unique fragment possesses great interest, since the only two 
Cretaceous species previously known were from the Gault. It is 
remarkable for the irregularity of its growth, the third whorl bulging 
to the left and the second to the right; this tendency perhaps pre- 
ceded the more regularly pupzeform shapes of the Gault species. 
In the genus Aporrhais I had grouped some ten species, including 
all those which resemble existing Aporrhais or the Oolitic Alaria in 
general form. I referred them all to Aporrhais, believing the 
principal character upon which Alaria had been founded was not 
constant in the living species. I find that although this is the case, 
and to the greatest extent in the recent 4. pes-carbonis, there is no 
such variation among the fossils, which differ further in the narrow 
produced wing and more elongated spire. I find it, however, incon- 
venient to place the very similar forms A. marginata and A. carinata 
in separate genera, as would be the case if any of the Gault forms 
were included in Alaria of Morris and Lycett, to which, especially as 
defined by Piette, they would perhaps strictly belong. Again, their 
facies differs considerably from that of the Jurassic forms, which 
have hitherto been almost the only ones accepted as referable to 
Alaria. It seems to me more simple to recognize Alaria as the 
Jurassic phase of the genus, and to group the Cretaceous phase in a 
separate sub-genus, for which the name Anchura has been proposed 
by Conrad, and generally recognized by American paleontologists. 
Alaria, which has been further restricted by Gabb, is characterized 
by him as follows :— 
Shell fusiform, spire elevated; anterior canal more or less produced, straight or 
curved; without posterior canal; outer lip digitate, formed at one or more stages 
previous to the adult age, and left behind by the growth of the shell, producing 
varices or tubular spines; inner lip thin. 
Sub-genus Anchura, Conrad (Drepanocheilus, Meck). 
Shell fusiform, anterior canal straight, more or less produced ;_ no 
posterior canal; outer lip produced into a single falcate process, 
generally if not always bearing a spur below, as well as above. 
This sub-genus comprises the species of Aporrhais formerly placed 
in Group II. and a fragment, from Upware, which is evidently the 
remains of a shell closely allied to A. carinella, although with far 
more strongly tuberculated keels. It is doubtless a new form, but 
so fragmentary as hardly to deserve a specific name. 
The species formerly placed in Group I. are still left in Aporrhais 
proper, for the sub-genus Perissoptera of Tate was founded to corre- 
spond more especially ‘‘ with that section of Aporrhais which has A. 
occidentalis as its type,”! yet A. marginata (P. Orbigniana, Tate), 
which is included in it, approaches far more closely to the recent 
1 Geol. Repert, for September, 1865, p. 98. 
