104 INFERIOR OOLITE AMMONITES. 



species of Ludwigia. Its characters would certainly cause it to be noticed much 

 sooner than Lioceras apertum ; and it occurs more frequently than that species. 

 Lioc. apertum, in fact, runs more chance of being regarded as a variety of this 

 form or of Lioc. v-scriptum. 



Plate XV, figs. 11 and 12, represent the type-form of the species, with part of 

 the mouth-border. The test is well preserved on the greater part of this 

 specimen. It was collected by myself at Louse Hill. Plate XV, fig. 13, gives the 

 largest specimen I have seen. It is slightly more compressed, is without 

 test except in the umbilicus, and shows a portion of the mouth-border. This I 

 also collected at Louse Hill. Plate XV, figs. 14 and 15, illustrate a specimen 

 which, together with figs. 7 and 8, was broken, but not irreparably, in transit from 

 the artist. It has the test well preserved, and is a typical young example. It has 

 no portion of the body-chamber present ; but it shows the characters of the species 

 very well, especially the nodose ribs on the inner area, and is useful for com- 

 parison with figs. 7 and 8. It came from Bradford Abbas. Plate XV, figs. 16 

 and 17, is a variety with slightly finer ornamentation and a larger umbilicus. 

 The test is well preserved ; but the artist has scarcely succeeded in giving a true 

 likeness of the fossil, because he has made the ribs too straight on the outer area, 

 and has not turned the ends sufficiently forwards. They are also too much 

 recurved in the middle. 



Ludwigia Lucti, S. Buckman. Plate XXI, figs. 3 — 11. 



Discoidal, somewhat compressed, carinate ; whorls broad, flattened (the sides 

 nearly parallel), and ornamented with broad, but obscure, bifurcate ribs, which are 

 recurved on the middle of the lateral area, and project forwards on the outer edge. 

 Ventral area smooth, very slightly convex, carrying a fairly distinct, but narrow, 

 carina. Inner margin deep and rather upright. Inclusion four-fifths of the 

 preceding whorl ; umbilicus rather deep, inclining to concave, and with well- 

 marked ribs on the visible portions of the inner whorls. 



Although this species seems to be most certainly scarce, yet, by a stroke 

 of good fortune, I have a series commencing with a specimen only 3 lines in 

 diameter. This is probably due to the fact that the fry of this species can be 

 definitely separated from the fry of the various species of Lioceras and Hyper- 

 lioceras. Generally it is almost hopeless to try to decide to which species, or 

 sometimes even to which genus, many of the small fry really belong. 1 



1 When we remember that the species of these genera possessed a common ancestor, and that 

 the younger the specimen the more we obtain a likeness to that ancestor, there is nothing more than 

 we should expect in not always being able to separate the fry with certainty. 



