. The anatomy, physiology, morphology and development of the blow-fly (Calliphora erythrocephala.) A study in the comparative anatomy and morphology of insects; with plates and illustrations executed directly from the drawings of the author;. Blowflies. DEVELOPMENT OF THE GENERATIVE ORGANS. 687 mind is to account for the occurrence of more than a single pair of these rudimentary organs. Ganin's observations on Platygaster, however, appear to be in favour of the existence of two pairs of such rudiments. These groups of cells re- semble the imaginal discs, and are solid ovoid masses of small epi
. The anatomy, physiology, morphology and development of the blow-fly (Calliphora erythrocephala.) A study in the comparative anatomy and morphology of insects; with plates and illustrations executed directly from the drawings of the author;. Blowflies. DEVELOPMENT OF THE GENERATIVE ORGANS. 687 mind is to account for the occurrence of more than a single pair of these rudimentary organs. Ganin's observations on Platygaster, however, appear to be in favour of the existence of two pairs of such rudiments. These groups of cells re- semble the imaginal discs, and are solid ovoid masses of small epithelioid cells measuring '2 mm. in their long diameter. I have no absolute evidence as to their true nature. The earliest stage in which I have been able to identify the gonads with certainty is the first day of the pupa state, when they are occasionally seen in sections as ovoid groups of small epithelial cells enclosed in a cellular mesoblastic capsule, which stains more readily than the cells enclosed within it. The long diameter of the capsule is '2 Fio. 98.—The ovary and testis on the third day of the pupa stage ; from dissections. /, testis ; d, duct of the testis ; 0, ovary ; g c, genital cord ; h, hypodermis. Seen with an inch objective. On the third day of the pupa I have succeeded in dissecting out both the ovaries and testes, which are now very distinct, and in sections exhibit a marked differentiation of structure. The Testis on the third day of the pupa is a glistening white reniform body "4 mm. in diameter. The genital cord is attached to it laterally at the hilus; this is a slender cellular cord invested by a distinct peritoneal membrane which extends backwards towards the apex of the abdomen ; it subsequently becomes thevas efferens. Its length is about i mm. ; it unites with its fellow at an acute angle, and forms the rudiment of the vas deferens, which is attached to the hypodermis a little in front of the position of the future anus. 45. Please no
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Keywords: ., bookcentury1800, bookcollectionbiod, bookdecade1890, bookyear1890
