552 



MYRIAPODA. 



appearance that they present towards their termi- 

 nation appear in some species 

 to perform likewise the office Fig. 315. 

 of reservoirs fo the seminal 

 fluid. In a large African species 

 Mr. Newport found the double 

 organ of intromission to be 

 prehensile (jig. 314, B, a), 

 each part having the form of a 

 distinct claw between the move- 

 able joints, of which passes out 

 the elongated half corneous 

 penis. These parts are co- 

 vered in anteriorly by a horny 

 valve somewhat of a trian- 

 gular form, and the whole oc- 

 cupies an oval space on the 

 under surface of the seventh 

 segment, corresponding to that 

 usually occupied by the legs. 

 " With regard to the product of 

 secretion in these organs," ob- 

 serves Mr. Newport,* " I have 

 never yet found any thing but 

 a granulous fluid in the cceca, 

 apparently similar to the gra- 

 nules in the higher animals 

 from which Spermatozoa are 

 produced, but this might have 

 arisen from the immature re- 

 cent specimens I was alone 

 able to obtain. It would be 

 interesting to ascertain whether 

 these germs of Spermatozoa are 

 produced in the cceca as there 

 seems reason to believe, as we 

 shall presently find that the ova 

 in the female are secreted in 

 sacs which appear to be ana- 

 logous to these cceca in the 

 male organs. I am inclined to 

 think that the Spermatozoa are 

 not developed until the granu- 

 lous fluid has passed into the 

 efferential ducts at the season of 

 impregnation." 



The female organs of the 

 JididtE (jig. 315) are described 

 with equal minuteness in the 

 paper above referred to, from 

 which we extract the following 

 exceedingly valuable observa- 

 tions, as nearly as possible in 

 the words of Mr. Newport him- 

 self, to whom we are also in- 

 debted for the illustrative fi- 

 gures. In the female Julus, the 

 organs of reproduction are as 

 simple as those of the male. 

 They consist of a single elon- 

 gated bag or oviduct, covered 

 on its exterior surface with a 

 very great number of ovisacs 

 or cceca of various sizes, each 

 of which secretes but a single 

 ovum. This oviduct extends 

 backwards beneath the alimentary canal, from its 



* Phil. Trans, for 1841. 



double vaginal outlet (a a), which is situated 

 in the fourth segment behind the second pair 

 of legs, as far as the posterior part of 

 rectum close to the anus, where it ends in a 

 cul-de-sac (d). It is most nearly in contact with 

 the alimentary canal on its upper surface, but 

 is separated from it by adipose tissue ; m 

 the pregnant female it is smooth, and dis- 

 tended with ova that have passed into it 

 from the ovisacs, and are ready to be de- 

 posited immediately after intercourse with the 

 male. The ova at the anal extremity, that 

 is, at the commencement, of the duct are 

 as perfect as those near the vaginal outlets. 

 The oviduct contains within its cavity, at least 

 from seventy to eighty of these perfect eggs 

 awaiting impregnation, arranged in two or more 

 irregular rows, and greatly distending its sides. 

 In some of the larger species of the genus 

 there are four and in others five rows of eggs, th 

 number of which is much greater than in our na- 

 tive species. The ovisacs (fg. 315 and 316 ? c c) 



Fig. 316. 



are little sacculi, distributed thickly to the num- 

 ber of many hundreds over the whole exterior 

 of the oviduct, from its posterior or ccecal ex- 

 tremity to within a short distance of its vaginal 

 outlets. Each ovisac, whatever be its state of 

 developement, contains but a single ovum, 

 every part of which is produced in it, from the 

 germinal vesicle in the most rudimentary form 

 to the yelk, albuminous fluid, and shell. This 

 fact deserves particular consideration. A large 

 proportion of the ova in the ovisacs never 

 arrive at maturity, but are retarded in their 

 growth by the more rapid developement of 

 others that are near them, so that on examining 

 an oviduct partially distended with ova, the 

 greater number of ovisacs in different states of 

 developement, are at the sides and on the 

 under-surface of the duct, in parts which corres- 

 pond to the interstices between the fully deve- 

 loped eggs, that have passed into the oviduct, 

 or are still forming on its exterior. One row of 

 ovisacs usually exists on each side of the duct 

 near its upper part, but most of the ovisacs in 

 the course of developement are at its sides. 



