ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 213 



carefully studied since the time of the older naturalists, the memoir 

 contains little of moment that can in any way he called new or of general 

 interest. The mouth-organs, the directive hairs, the manifold respiration, 

 the nervous system, are well described, and the accompanying figures are 

 very good. 



Some Species of Chermes.* — M. N. Cholodkovsky finds on young 

 Siberian cedars (Pinus cembra), on warm days in spring and summer, 

 woolly masses, which can even be detected in winter if the snow be 

 shaken off the branches. In winter and early spring these consist of 

 wingless females of Chermes which have outlived the winter ; in the 

 second half of April they lay amber-yellow stalked eggs ; in the second 

 half of May winged examples may be seen laying their eggs. This 

 species is allied to Chermes strobi. Soon there appear a number of small 

 yellowish-brown wingless individuals, which push their long proboscis- 

 setaa deeply into the tissue of the needles of the cedar ; these the author 

 regards as the sexual generation of this species of Chermes. Another 

 species has eggs which outlive the winter, and from which in spring 

 wingless forms are developed ; for this latter form the author proposes 

 the name of C. pectinata, and for the one which has some resemblance to 

 C. strobi that of C. cembrae. If the eggs which have survived the winter 

 are fertilized eggs, the resemblance of the life-history of Chermes to 

 Phylloxera would be more complete than Dr. Blochmann has imagined 

 it to be. 



B. Myriopoda. 



Post-embryonic Development of Julus.t — Mr. F. G. Heathcote has 

 followed up the post-embryonic development of Julus terrestris. 



(1) Cazlome. The somites divide into two parts, one in the body, the 

 other projecting into the legs ; the cavities together form the coelom. That 

 within the legs breaks up, and the cells form muscles. The body-part 

 unites dorsalwards along the thin sheet of mesoblast which unites it to 

 its fellow ; the two vesicle-like parts meet medianly above the nerve-cord 

 so as to form a single generative tube. The body-parts of antennas and 

 mandibles disappear ; those of the third pair form salivary glands ; there 

 are two pairs of somites to each double segment. (2) Generative organs. 

 The ova and follicle cells are proliferated from the walls of the above- 

 mentioned generative tube. (3) Nerve-system. There are two cerebral 

 grooves as in Peripatus, disappearing early ; the double ventral cords 

 concentrate in one ; the cavities of the ganglia vanish early ; there are 

 two ganglia to each double segment. (4) Trachese arise as epiblastic 

 invaginations behind the legs ; swell into two vesicles, each with two 

 diverticula, which break up to form the tracheal tubes ; there are two 

 pairs of invaginations to each double segment. The stink-glands are 

 epiblastic invaginations, with a muscular coat superadded later, one pair 

 to each segment. (5) Heart arises from mesoblast cells in body-cavity. 

 These cells were derived from hypoblast, form a network, and the heart 

 by a joining of the meshes of this network. The heart has two pairs of 

 arteries into spaces of fat-body, two pairs of ostia, an imperfect peri- 

 cardial membrane continuous with fat-bodies, and three coats — two 

 muscular and an outer connective. The fat-bodies arise from above 

 mesoblast network. (G) Body-cavity is a pseudoceele, distinct from the 



* Zool. Anzeig., xi. (1888) pp. 45-8. t Proc. Roy. Soc, xliii. (1887) pp. 243-5. 



