20 THORELL & LINDSTRÖM, SILURIAN SCORPION FROM GOTLAND. 



close to the borders of the cephalothorax, not far from its anterior angles. The dor- 

 sal and lateral eyes of Cyclophthalnius form almost a circle which occupies the greater 

 part of the cephalothorax^). The eyes of Patceophonus nuncdus are quite unknown; 

 but the Scotch Palteophonus would seem more to resemble the recent than the Carbo- 

 niferous scorpions, at least in the size of its dorsal eyes ^). 



A character of great importance, in which Palteophonus more nearly agrees with 

 the recent scorpions than with their allies from the Carboniferous period, is in the 

 structure of the sternum. In Pala3ophonus, at least in the Scotch species, this consists 

 of a single plate, as is also the case in the now living scorpions, whereas in the Car- 

 boniferous scorpions, or, at all events, in Eoscorpius euglyptus F'eac'R^) — the only spe- 

 cies of this period in which the ventral side of the anterior part of the body seems 

 to be tolerably well known — the sternum, according to the figure, is made up oithree 

 distinct plates, or, if the two plates in front of thera, situated between the coxas of 

 the second pair of legs, are also considered as sternal plates, it consists of ^ue*) plates. 

 The character of these two plates is considered in the sequel. 



Unfortunately for the study of the affinities of Palteophonus, but little is known 

 of its ventral side and of the organs attached to it. Whether this Silurian genus, like 

 all recent scorpions, was provided with maxillary lobes on its two anterior pairs of 

 coxa3, or whether it was destitute of maxillary lobes, as seems to be the case in Eo- 

 scorpius euglyptus, we are totally ignorant. Even of the pectoral combs (see above p. 

 13, note) too little is known to perrait us to make a comparison between them and 

 the combs of other scorpions. The structure of these organs seems to be more va- 

 riable in Carboniferous species than in recent Scorpions, and they often deviate con- 

 siderably from the combs of recent forms. Whilst in Cyclophthalmus — at least in C. 

 Kralupensis (see above, p. 17, note) — and in the typical species of Eoscorpius, E. 

 carbonarius Meek & Worthen, there is only a single row of small lamellte behind the 

 rhachis, corresponding to the »fulcra» of the comb-teeth in recent scorpions^), and 

 interinediate lamellcB are thus totally wanting''), some at least of Peach's species, for 

 instance E. euglyptus, seem to have a large number of such intermediate lamellse dis- 

 posed in three or more, more or less regular, rows. In this species the teeth are 

 said to form a clouble row at the free end of the comb, which is not the case in any 

 recent scorpion. In Cyclophthalmus Kralupensis, according to the figure given by Fritsch, 

 the rhachis of the comb consists oi four lamella^; in Eoscorpius again it seems to be 



') In the figure giveu by Fritsch, 1. c, of Cyclophthalmus senior Corda, it is at once seeu that the uumber 

 of the dorsal plates of the abdomen in this scorpion is seven, not eight, and that the limit between 

 the abdomen and the tail is very abrupt, the tail being at its base much narrower than the abdomen, 

 just as in all other known scorpions, Mazonia Woodiana Meek & Worthen certainly not excepted. The 

 movable fingers of both the mandibles have been löst in Corda's specimen, and this circumstance has 

 caused Peach to assume (1. c, p. 408) that the mandibles in Cyclophthalmus are monodactylous (»not 

 ohelate»). 



-) See above, p. 10. 



3) L. c, p. 402, Pl. XXX, figs. 3— 3c. See especially fig. 3a. 



*) The le1,ter press states four, the small (central) plate being apparently overlooked. 



ä) See T. Thorell, On the Classification of Scorpions, in the Ann. and Mag. of Nat. Hist., 4th Ser., XVII 

 (1876), p. 3. 



^) In the recent species there are alivays intermediate lamellae, disposed in 1 — 3 rows. 



