MYRIAPODA. 



451 



resemble Insect larva that little can be said 

 concerning them in addition to what the reader 

 will find elsewhere stated. (See articles AN- 

 NELIDA, CRUSTACEA, ARACHNIDA, INSECTA.) 

 The antenna upon the head, which are in- 

 variably two in number, correspond in all 

 essential circumstances with those met with in 

 Insects, and doubtless perform the same func- 

 tions. The eyes when present, which is not 

 the case in all the genera, exhibit the form of 

 simple ocelli congregated upon the head, and 

 arranged in lines or triangular patches ; but in 

 no case do they exhibit the appearance of a 

 reallj compound eye, such as is possessed by 

 the generality of Insects in their perfect state. 

 With respect to the other senses, touch, taste, 

 and smell, but little is known except by conjec- 

 ture, and presuming them to exist we can only 

 suppose them to be conferred in the same 

 manner as in the real Insect. 



Generative system.- A remarkable difference 

 exists between the Chilognatha and the Scolo- 

 pendroid Centipedes with respect to the posi- 

 tion of the organs of generation. In the former 

 the external openings, both of the male and 

 female genitals, are situated near the anterior 

 extremity of the body, as is the case among 

 the Annelida; whilst in the Chilopodous 

 genera, which exhibit a higher grade of organi- 

 zation, the generative apertures are found in 

 the caudal segment as in the Insects. 



In Lithobius the structure of these parts is 

 in both sexes very simple. In the male there 

 are three long and convoluted secreting tubes 

 resembling the simplest form of the testis in 

 Insects, wherein, doubtless, the seminal fluid 

 is elaborated. These are united at their termi- 

 nations so as to form a kind of common recep- 

 tacle, from which two tubes proceed to the 

 root of the intromittent organ, at which point 

 they are joined by four smaller auxiliary vessels, 

 which seem to take their origin in masses of 

 fatty substance. The penis is a horny cylin- 

 drical tube that can be protruded from beneath 

 a valvular plate which covers the anal orifice 

 (fig. 309, o). 



The female apparatus consists of a single 

 sacculated ovarium, occupying the mesian line 

 of the body. From tins proceeds a narrow 

 excretory duct, which, however, prior to its 

 termination beneath the anal segment becomes 

 considerably dilated into a cavity that has been 

 improperly named uterus. Here it receives 

 two sets of supplementary vessels, the one a 

 pair of wide cceca, the other composed of four 

 convoluted vessels apparently destined to secrete 

 some additional covering to the eggs before 

 their extrusion. The female generative orifice, 

 situated in the anal segment, is covered with a 

 horny plate and furnished with a pair of small 

 horny forceps calculated to assist in copulation. 



The male generative organs of Scolopenclra 

 present a very peculiar structure ; but these 

 we have already described elsewhere (see (JE- 



NERATION, ORGANS OF). 



The male generative organs of Julus (fg. 314. 

 A) are two elongated and partially convoluted 

 tubes placed side by side beneath the alimentary 

 canal immediately above the nervous system. 



The excretory ducts or terminations of these 

 tubes run towards the anterior part of the body, 

 where they terminate in two organs of intro- 

 mission (a), which pass out at the under surface 



Fig, 314. 



B 



of the seventh se:z- 

 ment by distinct ori- 

 fices behind the se- 

 venth pair of legs. 

 Posteriorly they ex- 

 tend backwards as far 

 a the middle of the 

 colon. In the ante- 

 rior third of their 

 course they lie close 

 together, but after- 

 wards separate, be- 

 come smaller, and have developed from their 

 sides at short distances a number of minute 

 glandular cceca, or transparent vesicles (c), which 

 doubtless constitute the secreting portions of 

 the apparatus or proper testes of the animal. 

 The two efferent ducts, whereby the secretion 

 of these cceca is conveyed out of the body, 

 inter-communicate fieely by short transverse 

 canals (Jig. 13, d d), and from the sacculated 



