242 



distinctly in our specimen, some being pushed under the head piece. The 

 trUobation is more marked on this part also than in its Dudley ally, and the 

 axis a central portion thus marked out is narrower than in H. delphinocephalus. 

 The tail, however, shows the distinction more strongly, the short trigonal tail 

 iece of the Dudley fossil being here replaced by a long triangular organ, pro- 

 luced into a stout thick mucro more than one thii-d the whole length of the 

 taiL It is sharp, but tha tip is not recurved. There are about nine furrows on 

 the central axis of the tail, and seven on the sides, and these join on to the 

 furrows on the axis, while they do not do so in the Dudley fossil. 



There is a species in the "Woolhope limestone which should be diligently 

 sought for by the Club, S. cylindricits, Salter (Trans., Pal. Soc. vol. xvii. 

 pi. xi., fig. 12, and woodciits), which in some respects is more like our ff, 

 Johannis th&n the Dudley fossiL But this has a narrower and more cylindrical 

 tail, with a much stronger and longer point ; and the back of the creature is 

 flat, with the sides turned sharply down. Its head is more like that of H, 

 delphinocephalus. I wish we could get perfect or numerous examples. 



Enough has been said to show that whUe the species of this genus differ 

 from each other sufficiently, they yet are like enough to be readily mistaken 

 for each other. What natural objects are there which may not be thus con- 

 fused by the careless observer ? It woxdd puzzle any body but a close scrutiniser 

 to recognise, under their varieties of colour, the true characters of humble bees, 

 or wasps, or ants ; but the practised entomologist knows them welL The 

 business of natural history observation is to detect these differences under the 

 mask of general similarity, which covers the species of all large genera. 

 Whether the species were derived from each other by long selection, according 

 to the true and earnest philosopher, Darwin, or whether created separately, 

 as some would have it (and there is about equal probability for both views, 

 since some fonns must have been original), the acumen of the naturalist is best 

 brought out, not by confusing himself with theoretical views, however probable, 

 but by close observation of the real differences which exist even between nearly 

 related species. 



H, JohannU was named in compliment to John Edward Lee, Esq., of 

 Caerleon, a true man of science and a true friend. 



