430 NATURAL SCIENCE. June. 



An objection that might strike even the casual reader of these papers 

 is that all the Lias and much of the Inferior Oolite had been passed 

 through before any of these so-called males appeared ; for the earliest 

 are those which Haug finds among the Sonninics. In the Ammonite 

 fauna of the Lias we have as yet only been able to notice one species 

 possessing the characters supposed by Munier-Chalmas and Haug to 

 denote the male sex. That species is Ammonites accipitris, J. Buckman, 

 which, as it occurs with Ammonites oxynoius, would be considered as 

 the male of that species. Now Ammonites accipitris is, unfortunately 

 for this hypothesis, a very rare form, which seems only to have been 

 found in this country, and in one restricted locality. Ammonites oxy- 

 notus, however, is common enough on the Continent, where it must 

 have lived in a state of single blessedness. But as for the rest of the 

 Liassic Ammonites, where are the males ? Or are we to suppose that 

 the two sexes were exactly alike, and that secondary sexual characters 

 were a comparatively latter-day Jurassic invention ? 



Objections such as these suggest the enquiry whether there may 

 not be some other explanation of the appearances that the French 

 authors are so ready to ascribe to sexuality. As that remarkably 

 Heavenly Twin, Angelica Hamilton-Wells, reminds us, " so 

 unwholesomely is the imagination of a man affected by ideas of sex." 



Now the characters that Munier-Chalmas has hit upon as 

 " masculine " are in great measure those which appear in the 

 different Ammonite-stocks or lines of descent when they draw near 

 the period of their extinction. They are, to a large extent, characters 

 such as we have learned to associate with the old age of a race, 

 when it is in a sense retrogressive. May we not then suppose that 

 these so-called males are in reality the final expressions of the various 

 races to which they belong ? At all events, Cadomocevas, CEcotraustes, 

 and CEcoptychius seem explicable as such retrogressive forms ; but 

 N ovmannites is admittedly a difficulty. 



The sexual hypothesis, however, is one about which it would be 

 foolish to dogmatise ; it deserves full consideration. Munier-Chalmas 

 and Haug say that they have many males yet unfigured ; and this state- 

 ment is borne out by other collections, so far as the Oolitic rocks are 

 concerned. It must be remembered that our knowledge of the 

 Ammonite fauna is as yet very imperfect, large though the number 

 of described species appears to be. Some of the Jurassic rocks have 

 been done very scant justice to, and their treasures are still unknown 

 to Ammonite literature. 



Apart, however, from any special hypothesis, there is one con- 

 sideration that may profitably be brought to the notice of those who 

 endeavour to discover signs of sex in the extinct Cephalopods. They 

 may be recommended to enquire whether such signs are to be found 

 in the living species of Nautilus, and if so, what those signs are. Of 

 course Nautilus is not an Ammonite, does not even belong to the 

 same Order of Cephalopoda ; still there can be very little doubt that 



