ZOOLOGY AM) 1«)TANY, MICROSCOPY. ETC. 745 



and are formed from the cytoplasm. The radiation of the reticulum has 

 not necessarily its centre in the nucleus of the cell ; very ditferent 

 cytoplasmic formations, such as the radiated vesicle, the sheath, and the 

 excretory tube, may afford insertion for the greater number of the radial 

 trabeeula?. 



Glandular Structure on Abdomen of Embryos of Hemiptera.* — 

 Mr. W. M. Wheeler describes on the first abdominal segment of embryos 

 of Cico'ln septemdecha a pair of invaginate glandular structures 

 apparently homologous with similar, but evaginate appendages on other 

 insects. In relation to the latter, there has been much diversity of 

 opinion, but the author's investigations on BJatta have convinced him 

 that they are neither sensory nor branchial organs, bnt glands, bo is it 

 with the invaginations seen on Cicada and Nepa. The function of the 

 apparently degenerate glands was probably odoriferous. 



Life-history of diermesf — Herr N. Cholodkovsky has continued 

 his observations on the life-history of Chermes. He lincls that C strobi 

 has no relation to G. coccineiis, but to a new and undescribi:d "species" 

 which he names provisionally C. sibh-icus. C. coccineus is found to 

 wander from the pine to the white tir, and in the succeeding summer 

 returns to the pine, where it lays the eggs which give rise to the black 

 males and females. Another " species " which the author calls C. 

 lappohkus, wanders, in St. Petersburg, on to the larch, and, therefore, is 

 an ally of C. hamadryas. The author must be understood to use these 

 new species merely for the purpose of better discrimination. Further 

 details are promised. 



Dr. L. Dreyfus J has a critical and destructive article on Prof. 

 Blochinann's recent essay ou the Cycle of Generations in Chermes ahittis. 

 For the details of the disj^ute, reference must be made to the original. 



Hypodermis of Periplaneta.§ — Dr. P. Mingazzini investigated the 

 hypodermis of Periplaneta orientalis to see if Minchin was right in his 

 conclusion that the dorsal hypodermis of the abdominal segments con- 

 sisted of two strata of cells, the outer chitinogenous, and the lower 

 ganglionic. There are indeed large inferior cells, but these are not 

 nervous, but merely epithelial, derived from the outer layer, and greatly 

 increased in size. They are ajjparently specialized glandular cells of 

 the epidermis, branched in form, large in size, and segregated from the 

 chitinogenous layer. As to a special gland discovered by Minchin on 

 the dorsal intersegmental membrane of the sixth abdominal ring, its cells 

 are quite homologous with those of the general stratum under discussion. 



Malpighian Tubules of Libellula depressa.ll — Dr. A. B. Griffiths 

 adds the dragon-fly to the number of animals in which he has found uric 

 acid ; it is to be found in the Malpighian tubes, in which no other 

 ingredient could be detected. 



y. Prototracheata. 



Brain of Peripatus.U — M. G. Saint-Eemy chiefly describes the 

 internal structure of the brain of Peripatus, as Balfour's account is very 



* Zool. Anzeig., xii. (1889) pp. 500-4. f T. c, pp. 387 91 



: Biol. Centralbl., ix. (1889) pp. 363-76. 



§ Atti R. Accad. Lincei (Rend.), v. (1S89) pp. 573-8. 



il Proc. R. Soc. Edinb., xv. (1887-8) pp. 401-3. 



4 Coniptes Rundiis, cix. (1889) pp. 315-7. 



