438 



PHOF. B. T. LOWNE OX THE STRUCTURE AND 



vatioiis beiog in complete accord witli those of the above-named 

 authors. 



3. "With regard to the structure of the so-called gum-glands of 

 Musca and probably of other insects, I would submit that a com- 

 parison of the description of the gum-glands, as I have given it, 

 with the ovary of some Arachnids, Crustacea, and Worms is not 

 \Ndthout interest, 



That such ova are developed within cells and present appear- 

 ances exactly similar to those I have described, is pretty evident 

 from the figures of the young ovary of Spiders given by Stuhl- 

 mann (25), plate ix. figs. 190 and 197, and plate x. figs. 214, 

 215, and 216; whilst similar appearances are represented by 

 Van Beneden (3, 4, and 5) in the germogen of the solid-bodied 

 Worms and some Crustaceans. It is true these authors put a 

 different interpretation on the relation of the ova to the epi- 

 thelium of the germogen ; but the fact remains that their figures 

 are such as to show the close resemblance of the germogen in 

 these animals and the so-called gum-glands of the fly. 



4. With regard to the morphology of the gum-gland, so long 

 as we remain ignorant of the precise manner in which this struc- 

 ture and the common oviduct are developed, its morphology will 

 remain more or less doubtful. I have already given my reasons 

 for the belief that the common oviduct is part of the primitive 

 ovary ; and this opinion is generally held. The condition of the 

 parts in the Hydrophilidae is an undoubted indication, I think, 

 that the gum-glands are merely modified ovarian tubules, and 

 have a similar origin from the primitive ovary ; the connexion 

 which persists between these glands and the calyx of the ovary in 

 the fly is not, I think, unimportant in this relation. In the 

 Hydrophilid83 the gland is comparable with the germ-gland of 

 the Crustacea. Compare the figures given by Van Beneden (5) 

 and by Stein (24). 



It is true that Palmen (21) states that the appendicular glands 

 (the gum-glands and the spermatophorous capsules) have the 

 same origin from the ectodermal invagination as the vagina and 

 uterus ; but his observations are general, and he believed the 

 gum-glands to open into the uterus. 



5. Supposing my corpuscle to be a germ-ovum, its discharge 

 from the cell in which it is developed may^be considered an un- 



