528 SUMMARY OF CURRENT RESEARCHES RELATING TO 



continuous, it may be accelerated in times of danger. There seems no- 

 doubt that the organ is a defensive odoriferous gland, like that in many 

 beetles. 



Intestinal Secretion in Crickets.*— L. Leger and 0. Duboscq describe 

 (1) the secretions included in the epithelium of the mid-gut of GryLlus 

 campestris and G. domesticus ; (2) the expulsion of these secretions ; and 

 (3) their appearance when free in the lumen of the intestine. 



The facts described suggest that the secretion consists in a chro- 

 matolysis of the nuclei of the epithelium, which may divide amitotically 

 during their emigration. The nuclei seem to degenerate into a hyaline 

 substance. The nucleolus does not seem to have anything to do with it. 

 Perhaps the main interest of the research is in the analogy between the 

 figures of mid-gut secretion in insects and those given by Heidenhain 

 and by Nicolas in respect to intestinal secretion in Vertebrates. 



Collembola of Switzerland.^ — Dr. Job. Carl publishes the second 

 instalment of his work on this subject. He adds seventeen species, 

 some of them new, and one variety to the list, giving a present total of 

 ninety-three species and sixteen varieties. 



3. Myriopoda. 



Absence of Variation in a Swarm of Myriopods. X — A. V. Mauck 

 reports on a swarm of myriopods (Fontaria virginiensis) which lasted 

 during the early hours for a few days in August 1898, near the 

 Indiana University Biological Station at Vawter Park. " Other swarms 

 of myriopods have been reported, and are comparable with the swarms 

 of the Palolo worm during its breeding season." [Is not this going 

 rather far?] Pullman § has described the swarms of this same Fontaria 

 virginiensis; Verhoeff|| has told how the migration of Brachyiulus 

 unilineatus made a railroad track in the Hungarian district of Alfold so 

 slippery that a train was unable to proceed, though the rails were 

 sanded. 



Of the swarm Mauck reports, 1300 individuals were preserved for 

 statistical study, all adults and all about the same size. Males (with 

 30 pairs of legs) formed 47*517 p.c. ; females (with 31 pairs of legs) 

 formed 52 "4828 p.c. No variation was observed in the number of 

 segments, nor in the number and symmetry of the limbs, nor in the 

 number (7) of antennary segments. 



Ventral Nerve-Cord of Myriopods. 1[ — Dr. G. Rossi notes that in 

 lulus terrestris the nerve-cord is a flattened cylinder without ganglia, 

 commissures, or connectives. Four pairs of nerves (pedal and lateral) 

 occur in each movable segment of the body. The cord consists of four 

 parts : — (1) an external, nucleated sheath ; (2) a lacunar or reticular 

 tissue with numerous tracheae ; (3) unipolar pyriform granular nerve- 

 cells, especially on the ventral side ; and (4) an internal mass of nerve- 

 fibrils. 



* Arch. Zool. Expe'r., viii. (1900) Notes et Revue, pp. xlix.-lvi. (19 figs.). 



t Rev. Suisse Zool., ix. (1901) pp. 243-78 (1 pi.). 



X Amer. Nat., xxxv. (1901) pp. 477-8. 



§ Bull. U.S. Nat. Mus., 1893, No. 40, p. 75. 



|| Cf this Journal, 1900, p. 667. 



«j[ Atti (Rend.) R. Accad. Lincei, x. (1901) pp. 319-24 (3 figs.). 



