1886. ] Geology and Paleontology. 271 
the ventral side of the body; for in these and perhaps in all scor- 
pions, the dorsal plates increase in length, counting from front 
backward, so that the first plate is the shortest of all; whereas (at 
least in recent scorpions) the first ventral plate is /onger-than the 
following ones, corresponding in length and position to ‘wo or 
even three (2d and 3d, or 1st—3d) dorsal plates taken together.’ 
If the above given interpretation is, as I believe, the right one, 
the want of sfzracu/a on the plates needs no further explanation” 
Mr. Whitfield thinks that, whereas modern scorpions carry the 
tail (postabdomen) arched upward over the back, Proscorpius, and 
also Palzeophonus, carried it inthe opposite way, or curved down- 
w This would indeed be a character of fundamental impor- 
tance in distinguishing the Silurian scorpions from all other 
members of the group; but to me it is impossible to find any 
stringent reason for adopting this strange hypothesis. In the first 
place, it would seem that the animal’s gait would become exceed- 
ingly difficult and awkward, if it were to walk with its tail curved 
under the body ; and when it wished to kill, with the sting, the 
prey which it had caught with the hands of the palpi, it would 
ly be obliged to thrust the palpus with the prey between its 
legs, under the body, in order to bring it within the reach of the 
sting—no doubt a difficult performance for the animal. That in 
the embryo of scorpions the tail is bent under the body, is of 
course no reason for believing that the tail retains that position 
after birth, in the earliest or Silurian species, rather than in Car- 
boniferous and recent ones. As to Palzeophonus, I do not enter- 
‘eophonus nuncius described and figured by Professor Lind- 
trom and myself’ The basal joints of the tail of this animal are 
destroyed but must have turned their upper or dorsal surface 
upwards, as they have left the impression of their ventral part on 
wus" a specimen of Buthus 5-striatus Hempr. et Ehr., for instance, whose abdo- 
of cpreabdomen) is 2414™™ long, the length of the first ventral plate is 6™™, that 
2E ñrst three dorsal plates taken together 5%4™™. 
oot if the plates in question really were ventral plates, the first (or sixth, whe 
Mmea behind forward) would from its position seem to correspond to the 
z ween ‘ f 
of int segment of the abdomen, quite as the plate between the combs is the sternite 
Bo second segment. 
Thorell and Lindström, on a Silurian scorpion from Scotland (K. Svenska 
Vetenskaps-Akademien Handlingar, Bd. 21, No. 9). ae 
