SOLPUG1D3.] A II A C II N I D A speak of the " labre," but it is evident from their descrip tion that a portion of the languette is alluded to, not the part mentioned above as representing the labium. The abdomen is oblong, oval, or somewhat elliptic in its form, about equally convex above and below, and composed of nine or ten articulations, which decrease in breadth from the fore to the hinder extremity ; it is closely united to the cephalo- thorax throughout its entire breadth. The external orifice leading to the organs of generation is situated at the pos terior margin of the first articulation, and besides the two stigmata before alluded to, behind the basal joints of the second pair of legs, there are two other stigmatic openings 1 at the hinder margin of each of the second and third arti culations of the abdomen ; these stigmata are protected by a kind of comb-like fringe, and the anal orifice consists of a long vertical slit situated at the extremity of the terminal articulation. INTERNAL STRUCTURE. The Muscular System of Solpu- gids appears to be very similar to that of other Arachnids ; it has been fully displayed by Dr M. Kittary in the work quoted in note, of the present page. ^ The Respiratory System is tracheal and complicated. Five (according to Dr Kittary) openings at the hinder margins of the second, third, and fourth sub-abdominal articulations, lead to the abdominal trachea ; these consist of three longitudinal parallel tubes, into the outer one of which the short branches from the external openings lead, and with these are connected various other branches supply ing air to the different parts of the body. The abdominal tracheae also lead into thosd of the cephalo-thorax, which have their outer openings (two in number) behind the basal joints of the second pair of legs. The thoracic trachese send branches into the legs, palpi, and falces. There is probably some variation in different species in the details of their respiratory organs. Galeodes Araneoides, for instance, does not appear to have the fifth outward opening in the abdomen (fig. 15). The Circulatory System consists of an elongated dorsal vessel or heart, running from the middle of the cephalo- thorax backwards through the connection between the thorax and abdomen, but does not reach the hinder ex tremity of _ the latter. The thoracic portion is of an oval form, but it contracts in passing into the abdomen, enlarg ing again gradually as it runs backwards. Dr Kittary does not appear to have traced the various vessels which, no doubt, exist to convey the vital fluid from the heart to the different parts of the body. The Organs of Digestion consist of an elongated stomach in the cephalo-thorax, with lateral caeca ; this stomach is con tinued backwards into the abdomen in the form of a long single intestinal canal, leading into a cloaca at its posterior extremity. A kind of branching network of minute vessels secrete urine, and convey it from the whole abdominal mass by several main branches into the hinder part of the intes tinal canal. Beneath the stomach is an organ described as probably the liver, and another answering to the pancreas. The Nervous System is not particularly complicated, but bears great resemblance to that of other Arachnids, espe cially of the Araneidea. It consists of one large principal ganglion, or united pair of ganglia, from which branch nerves are sent off in all directions to the different parts and extremities of the body ; that which runs to the hinder extremity of the abdomen has an enlargement or kind of ganglion in its course. The Organs of Generation are highly developed in the 1 Dr Kittary in "Anatomische Untersuchung der Geineinen (Galeodes arancoules) and der furchtlosen (Galeodes intrepida) Solpuga," Bull. Afosc 1848, No. iv. tab. vi. fig. 2, b, b, b, indicates in G. intrepida, a ifth stigmatic opening at the hinder margin of the fourth abdominal articulation. 281 female, consisting of ovaries, and an oviduct leading to the external orifice. The male organs do not appear to be known. The Solpugidea are probably oviparous. 2 _ The order Solpugidea comprises a single family, Galeodulcs, divided into five genera, characterised principally according to the number of the subdivisions of the tarsal joints of the second, third, and fourth pairs of legs : 1. Jihax (Hermann), the tarsi all one-jointed. 3 2. AcUopus (Koch), tarsi two-jointed ; those of the hinder pair destitute of claws (Koch). 3. Galeodes (Olivier), tarsi of the second and third pairs two-jointed, and of the fourth pair three-jointed. 4. Solpuga, tarsi of the second and third pairs four-jointed and of the fourth pair seven-jointed. 5. Gluvia (Koch), all the tarsi undivided, i.e., consisting of a single long thin joint. Fifty-two species (of all the genera) have been described. See a recent paper, List of the Species of Galeodidcs, by A. G. Butler ; also the older work of Koch, Die Arachnid-en. All the species, though varying considerably in size, are remarkably similar in general iorin aiil appearance, and nearly all are of sombre colouring. GENERAL REMARKS. The Solpugidea are nocturnal in their habits, living by day secreted under stones, among debris and rubbish, and in old ruined walls and buildings, in dry sandy places ; from such retreats they come forth at night, and run with great swiftness. A recent traveller in Palestine relates, that when living in tents on the plains of the Jordan, near Jericho, each night, as nearly as possible between half-past nine and ten o clock, several Solpugids entered the tent-door, running and racing with great speed over everything tables, chairs, and beds just like mad creatures, but apparently with no definite object, perhaps only attracted by the lights burning in the tent. When dis turbed in their diurnal hiding-places they showed fight and were extremely pugnacious ; but their being venomous is doubtful, though the Arabs seemed to dread them quite as much as they dreaded the true scorpions, which were also numerous under the large stones lying about. Some inter esting details of the voracity and habits in confinement of a species of Galeodes, are given by Captain T. Button, Ann. and Mag. N.H., 1843, vol. xii. p. 81. Like the Phalang- idea, it swallowed the solid parts of insects, and even of a lizard five inches long. Captain H. assumes, as one use at all events, of the palpal organ mentioned above, that it is " a retractile sucker," to enable it to ascend smooth surfaces. This, however, is very questionable. Order V. SCORPIONIDEA. In spite of differences in their internal anatomy, which appear to ally the Pseudo-Scorpionides more to the spiders than to the true scorpions, some leading features of ex ternal structure seem to stamp them at a glance as most nearly related to the latter. The impression inevitably created on a comparison of the true and false scorpions is that the latter are little scorpions without tails. Including them, therefore, here in the same ordinal group as the true scorpions, we may shortly characterise the order as follows : Body elongated-oval; cephalo-thorax of one undivided piece, hard, horny, and often tuberculated or granulose, while traces of thoracic segments soldered together are generally more or less perceptible. Abdomen united to the cephalo- thorax throughout its entire breadth, and composed of several segments formed by articulated transverse coriaceous plates on the upper and under sides, united by two lateral cartilaginous membranes. Falces didactyle ; palpi ter minating with a didactyle claw or pair of pincers ; the coxal joints of the legs, fixed to the lower side of the thoracic segments, form a kind of sternum; the sternal plate, properly so-called, being either wanting or very 2 A more recent work on Solpugidea than that of Dr M. Kittary, is by L. Dufour, Mein. Acad. Sc., torn. xvii. pp. 338-446, 186 J. 8 According to Koch, and also to Savigny, in his excellent figures. Dufour, who, I.e., says Rhax has two-jointed tarsi, evidently had a species of some other genus before him, probably Aellopus (Kccb), or else reckoned the metatarsus as a part of the tarsus.
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