908 SUMMARY OF CUJUtENT RESEARCHES RELATING TO 



Development of Male Generative Organs in Lepidoptera.* — 

 Dr. C. Spichardt lias investigated tho results of his observations of 

 the development of tlio male genital organs and efferent ducts in 

 Lepidoptera. 



The adult testes are first described, with special reference to 

 Liparis dispar. They consist of round bodies, about 1£ mm. in 

 diameter, lying dorsally in the middle lino of tho fourth abdominal 

 segment, between intestine and dorsal blood vessel. Three layers 

 ensheath tlie testis : (a) an outer peritoneal envelope of connective 

 tissue, serving for nutrition and protection, and not penetrating be- 

 tween the follicles ; (Jj) a muscular sheath, penetrating between tho 

 follicles, and present worn very early stages; (e) tho tunica propria, 

 lining the inside of the follicles as a transparent homogeneous mem- 

 brane, with irregularly scattered nuclei. Within these lie the eight 

 follicles, of a conical shape, with tlie point directed inwards. Tho 

 follicles contain spermatozoa at all stages of development, and ripest 

 towards the centre. 



The efferent ducts and vesiculse scminales. — Tho efferent ducts 

 expand in a funnel-shaped fashion, embracing the testis. Their walls 

 aro lined by high cylindrical cells, and a thin membrane forms an 

 external sheath. Variations in several different forms are noted. 

 From tho secreting seminal vesicles the ducts continue separate 

 almost to tho penis, where they gradually unite. 



Ejaeulatory duct and penis.— The chitinous cylindrical penis lies 

 below tho rectum, and stretches through two segments. From about 

 tho middle of tho penis tho ejaeulatory duct arises, uniting with 

 tho end of the efferent canals, from which it is markedly distin- 

 guished by its muscular walls. Liko the penis, it has an ectodermal 

 origin, but it exhibits no chitinous sheath. The erector and adductor 

 musculature is then described. 



The development of the testes. — Dr. Spichardt's chief results on this 

 point are thus summarized: — 



(1) The generative organs appear at a very early stage. They 

 ariso in the " Hautfaserblatt," and arc thus probably of mesodermic 

 origin. (2) Between the four primitive cells there are a number 

 (usually four) of nuclei, of doubtful import, from which the germinal 

 rudiment probably arises. (3) The incipient generative organ is 

 onsheathed in a fine membrane with scattered nuclei. (4) Tho four 

 primitive cells multiply by indirect division, until (5) the four follicles 

 are formed by invagination of the outer sheath. (6) A second en- 

 velope, the peritoneal sheath, originates from the fatty body. (7) Tho 

 nuclei within tho cells increase by repeated direct division, from thrco 

 to five times. (8) From this division there probably originate tho 

 small nuclei, which clothe the colony externally, and probably give 

 rise at a subsequent stage to the membrane of the sperm-bundles. 



(9) Protoplasm gathers round the nuclei, so that cells become 

 separate from one another, and leave a freo space in the interior. 



(10) The nuclei divide into many smaller nuclei, round which the 



* Ver. Naturh. Ver. Rhcinlande, xliii. (188G) pp. 1-34 (1 pi.). 



