54S 



MYRIAPODA. 



er adult animal, but subject to important and 

 very remarkable varieties during the progress 

 of its growth. In the lower forms, such as 

 J ul us (fg. 304), the texture of the segments 

 is hard, crustaceous, and brittle; but in the 

 Scolopendroid races, the rings are flattened 

 and covered above and below with tough and 

 coriaceous scutse. In all the Chilopoda each 

 segment supports only a single pair of ambu- 

 latory legs, which resemble in many respects 

 those of insects, but terminate invariably in 

 a simple claw. In the Chilognatha, on the 

 contrary, with the exception of a few of the 

 most anterior, and likewise of the terminal 

 or anal segments, each ring has two pairs 

 of feet attached to its under surface, con- 

 sisting apparently of two half segments con- 

 joined; and this view of their composition is 

 further strengthened by the fact, that a deep 

 transverse indentation or groove is always visi- 

 ble upon the dorsal surface, dividing the other- 

 wise apparently single ring into an anterior 

 and a posterior moiety, to each of which is 

 fixed a pair of short and very feeble legs, com- 

 posed of several distinct articulations. The 

 three first segments in Julus form exceptions, 

 however, to this arrangement, each of these 

 supporting only a single pair of ambulatory 

 feet, and these segments have been supposed 

 by some authors to represent the thoracic seg- 

 ments of the true insects. The seventh ring, 

 likewise, in the female, has one pair deficient, 

 they being replaced by the orifices leading to 

 the sexual organs. The anal and penultimate 

 segments are completely apodal in the Julidae, 

 whilst, on the contrary, in some of the Chi- 

 lognatha, the size of the locomotive limbs in- 

 creases progressively as we approach the caudal 

 extremity, the last segment supporting the 

 longest pair, which are directed backwards, so 

 as to have in some measure the appearance of a 

 furcate tail. 



In the Scolopendridtz (Chilopoda, Latr.), a 

 family which embraces those forms of Myria- 

 poda that are most nearly allied to Insects, we 

 have a race of carnivorous Myriapods, pos- 

 sessed of strong and active limbs, varying in 

 number in different genera from fifteen to 

 twenty-one pairs, by the aid of which they can 

 run with considerable rapidity, and are able, 

 owing to the flexibility of their long and 

 jointed bodies, to wind their way with facility 

 among the lurking places of Insects, against 

 which they carry on an unrelenting warfare. 

 All of them are found carefully to avoid the 

 light, and generally to frequent damp situations, 

 more especially where decaying animal or vege- 

 table substances abound. They lurk, therefore, 

 under stones or pieces of old wood, or are met 

 with beneath the bark of trees, localities which 

 from their structure they are peculiarly adapted 

 to occupy. 



In the following account of the anatomy 

 of these creatures we shall select the Scolo- 

 pendra, properly so called, for particular de- 

 scription, as being the largest and, conse- 

 quently, most commonly met with in our 

 collections, noticing, however, as we proceed, 



such peculiarities as may be worthy of notice 

 in other genera. 



The Scolopendrae have their bodies com- 

 posed of twenty-one segments exclusive of the 

 head, to each of which is attached a pair of 

 jointed legs. The segments are all of them 

 more or less quadrilateral in their shape, their 

 transverse diameter being generally the longest, 

 but their size is very variable and irregular. 

 The whole body is depressed, each segment, 

 consisting of a dorsal and a ventral plate of 

 soft but corneous consistency, formed by a 

 thickening of the cuticle in those regions of the 

 body, while the sides to which the legs are 

 appended, and where, moreover, the respiratory 

 spiracles are situated, are soft and of a coria- 

 ceous texture. 



The legs are all five-jointed and terminated 

 in a simple sharp horny claw : those appended 

 to the segments in the neighbourhood of the 

 head are comparatively small, but as they ap- 

 proximate the hinder part of the body they 

 increase in size and strength, the last pair being 

 turned backwards so as scarcely to be useful 

 as locomotive agents. 



The head, and more especially the parts 

 entering into the construction of the oral ap- 

 paratus of these Myriapoda, present many 

 difficult inquiries to the scientific entomologist, 

 who would attempt to identify them with ap- 

 parent'y corresponding structures met with in 

 the organization of the mouth of insects, and 

 accordingly we are not at all surprised to find 

 that no two authors agree as to the names that 

 are most applicable to the different pieces be- 

 longing to this portion of their economy. The 

 Myriapoda, be it remembered, are obviously 

 an osculant or transition group allied at once 

 to the Annelidans, to the Insecta, to the Arach- 

 nidans, and to the Crustacea. It is by no 

 means surprising, therefore, that, in the con- 

 struction of almost every part of their bodies, 

 we find an organization intermediate between 

 these important divisions of articulated animals, 

 as we shall again and again have occasion to no- 

 tice. But, perhaps, in no part of their economy 

 is this intermediate structure better exemplified 

 than in the mouth of the Scolopendra, to the 

 different portions of which all writers appear 

 to have given names rather in conformity with 

 their own preconceptions than with any real 

 affinities that have been pointed out, or any 

 general view of the real nature of such appen- 

 dages. With all respect for the opinions of 

 preceding writers, we shall, on this account, 

 endeavour, in the following description, to 

 avoid as much as possible technicalities pecu- 

 liar to the orismology of any particular branch 

 of zoological science. 



The head of a Scolopendra, or that portion 

 of the creature which supports the instruments 

 of sensation and the organs employed for the 

 prehension of food, appears, when viewed 

 superficially, to consist of two segments, one 

 a circular shield-like plate, constituting the real 

 head, that exists only upon the dorsal aspect 

 of the body, in which are inserted the antennae, 

 and which, moreover, contains the eyes and 



