782 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
into two sub-orders, Entognatha (Campodeidae, Japygidae, Collembola) 
and Ectognatlia (Machilidae and Lepismidae). 
y. Prototraeheata. 
Peripatus in Jamaica.* — Messrs. M. Grabham and T. D. A. 
Cockerell report the rediscovery of Peripatus in Jamaica ; the species 
is considered to be identical with that found by Grube many years ago ; 
it is very closely allied to P. Edwardsi as described by Mr. A. Sedgwick, 
but has a larger number of legs. The authors propose to call it 
P. jamaicensis, and fuller details are promised. 
5. Arachnida. 
Liphistius and the Classification of Spiders, f — Mr. R. I. Pocock 
proposes to divide the Araneae into the two groups of the Merothelae 
and the Opisthothelse ; the former will contain Liphistius only, in which 
the spinning appendages retain their embryonic position in the middle 
of the lower surface of the abdomen, whereas in the latter these ap- 
pendages migrate to the posterior end of the abdomen. Other points of 
distinction are — the Merothelae have eight, the Opisthothelse never 
more than six spinning mamillse ; in the former there are on the 
upper surface of the abdomen nine distinct tergites and on the lower 
two distinct sternites, while the latter have no distinct tergal plates to 
the abdomen, and the abdominal sternites persist only as the pulmonary 
opercula and the epigyne. 
Liphistius , therefore, appears to be a transitional form between the 
Opisthothelse and the Phrynidae, and it retains embryonic characters 
which all other Spiders lose. It would appear, also, to possess the 
homologue of the cribellum, and if so, its presence in widely different 
genera of other Spiders can be easily explained, and the possession of 
this organ loses the importance ascribed to it by Bertkau and Simon. 
Similarly, the fact that Liphistius has three well- developed claws to the 
feet, may explain the fact that genera of the Opisthothelse which are 
not naturally allied may appear to be so by having three or two claws. 
Mr. Pocock, therefore, proposes to divide the Opisthothelse into the 
Mygalomorphae (Aviculariidae and Atypidae) and the Arachnomorphae 
(Hypochilidae, Dysderidae, and others), and to distinguish them thus ; 
in the former the plane of the joint of the mandible with the cephalo- 
thorax is nearly vertical, while in the latter it is nearly horizontal ; 
in the latter the posterior lung-sacs are nearly always replaced by 
tracheal tubes, and they have six spinning mamillae, whereas the 
Mygalomorphae have ordinarily four. 
Observations on a Scorpion. :[ — Herr 0. Greve gives an interesting 
account of a scorpion ( Centrums hiaculeatus Lucas) from Central 
America, which came to Moscow encased in a wood-block. He kept it 
alive from September until May, and watched its movements, its occa- 
sional seizure of a cockroach, its thirst for water, its attempts to sting, 
the subsequent fatigue, and so on. For a short time Herr Greve also 
kept the larva of one of the Blattidae (unidentified) from the same source. 
* Nature, xlvi. (1892) p. 514. 
t Ann. and Mag. Nat. Hist., x. (1892) pp. 306-14. 
X Zool. Jahrb., vi. (1892) pp. 461-4. 
