SECRETORY PHENOMENA IN SILK GLAND. 427 



6. Mitochondria are present in all parts of the gland, but only 

 in the posterior region do they show definite orientation. 



7. Two membranes are present along the course of the gland, 

 and external tunica propria, and an internal tunica intima. 



8. Two substances regularly appear to constitute the silk 

 thread in the anterior region. This condition is found to con- 

 tinue more posteriorly after fixation with the Champy, Gatenby, 

 Benda, and Bouin methods. 



9. A substance similar to mucous surrounds the silk thread in 

 the middle region but does not extend into the anterior portion. 

 The origin of this substance has not been determined. 



LITERATURE. 

 Blanc, M. Louis. 



'89 Etude sur la secretion de la soie et la structure du brin et de la bave dans le 



Bombyx mori. Lab. d'Etudes de la Soie, pp. 53~9 8 - 

 Cowdry, E. V. 



'24 General Cytology. Univ. Chic. Press, Chicago, 111., p. 318. 

 Emberger, L. 



'25 Les mitochondria sont-elles des catalyseurs? Bull. d'Histologie (Physiol. 



and Path.), Vol. 2:12, pp. 3O9~374- 

 Gilson, G. 



'94 La soie et les appareils sericigenes-I. Glandes sericigenes des Lepidopteres. 



La Cellule, Vol. X., pp. 39-42. 

 Helm, F. E. 



'76 Uber die Spinndriisen der Lepidopteren. Zeit. fur wiss. Zool., Vol. 26, 



pp. 434-469. 

 Imms, A. D. 



'25 A General Text-book of Entomology. Methuen & Co., Ltd., 36 Essex St., 



W. C. London, p. 407. 

 Korshelt, E. 



'96 tiber die Struktur der Kerne in den Spinndrusen der Raupen. Arch. f. 



Mikroskop. Anat., Vol. 47, pp. 500-569. 



'97 Uber die Bau der Kerne in den Spinndrusen der Raupen. Arch. f. Mikro- 

 skop. Anat., Vol. 49, pp. 798-803. 

 Ludford, R. J. 



'25 Nuclear Activity in Tissue Cultures. Proc. Roy. Soc., Vol. 98: 692 (B), pp. 

 Marshall, W. S., and Vorhies, C. T. 



'06 Cytological Studies on Spinning-glands of Plalyphylax designatiis Walker. 



Intern. Monatschr. f. Anat. u. Phys., Vol. 23, pp. 397-420. 

 Maziarski, S. 



'n Recherches cytologique sur les phenomenes secretaires dans les glandes 

 filieres des larves des Lepidopteres. Arch. f. Zellforsch., Vol. 6, pp. 



397-433- 

 Meves, F. 



'97 Fiir Structur der Kerne in den Spinndrusen der Raupe. Arch. f. Mikroskop. 

 Anat., Vol. 48, pp. 573-578. 



