ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 239 



segment. In the male there are tliree extra pairs of appendages, 

 copulatory in function ; two pairs of these bear stridulating organs, 

 ■which have not been previously noticed in this genus ; besides the 

 chitinous ridges on these appendages, there are similar ridges on the 

 inner surface of the large terminal tergite. 



The tracheal system differs from that of most other Diplopods in 

 having very well developed branching tracheae. Each tracheal plate 

 carries a stigma, which opens into a " tracheal sac " ; from this sac 

 two main tracheal trunks pass out, each of which breaks up into a 

 number of smaller branches. The author considers the tracheal sacs 

 homologous with those oi Peripatus, from which form these branching 

 tracheae are derived. The antennary sense-organs are conspicuous. 

 An error is pointed out in the description of their histology by 

 Biitschli, who mistook certain cells, in the connective tissue sur- 

 rounding the nerve-bundles, for ganglion-cells. An auditory organ 

 is presupposed by the existence of a stridulating organ ; the 

 cavity opening to the exterior by a small pore below the eye, is 

 regarded, as such an organ ; it is lined by a sensory epithelium, sup- 

 plied by nerve-fibres from the cerebral ganglion. 



Anatomy of Myriopoda.*— Mr. T. D. Gibson-Carmichael, after 

 referring to Plateau's paper on the digestive tract of the Chilopoda,f 

 describes that of Lithohius, and compares it with that of Geophilus 

 longicorms and Himantarium Gdbrielis. He finds pure ui'ic acid in 

 the two Malpighian tubercles of the first form, but could find no saliva 

 in the so-called " salivary glands." 



y. Prototracheata. 



Fertilized Ovum of and Formation of Layers in Peripatns.J — 

 Mr. A. Sedgwick finds that the fertilized ovum of Peripatus capensis 

 has a large nucleus, of which three different stages are described ; in 

 the fii'st it is a spherical structure (diameter • Oi mm.) made up of a 

 fine spongework of very pale fibrils which are continuous with the 

 nuclear membrane, and the septum formed by it ; the membrane and 

 septum appear to be precisely similar in structure with the strands of 

 the external protoplasmic reticulum, and the latter are continued 

 directly into the former ; in the second form the chromatin of the 

 nucleus instead of being, as in the first, aggregated into a number of 

 small masses, is diffused through the nuclear reticulum ; in the third 

 the nucleus is divided into chambers by a number of septa, which 

 are continuous externally with the extra-nuclear protoplasmic reti- 

 culum. In the spindle form of the nucleus, the spindle was of 

 enormous size and appeared to be composed of the ordinary reticulum. 

 Mr. Sedgwick thinks that these observations confirm Dr. Klein's 

 view of the continuity between the reticulum of the nucleus and that 

 of the extra-nuclear protoplasm. 



The fully segmented ovum is found to be a syncytium in which 

 there are not, and have not been at any stage cell-limits. The at first 



* Proe. R. Phys. Soc. Edinburgh, 1885, pp. 377-81. 

 t Mem. Acad. R. Sci. Beige, xlii. (1878) 94 pp. (3 pis.). 

 X Proc. Rov. Soc., xsxix. (1885) pp. 239-44. 



