Pseudo-helminths : points in the natural history of a nematode worm / by Jabez Hogg.

  • Jabez Hogg
Date:
1888
Catalogue details

Licence: Public Domain Mark

Credit: Pseudo-helminths : points in the natural history of a nematode worm / by Jabez Hogg. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    rounded off, turns sharply on itself to form a clift and an open- ing, in which are placed the organs of generation. The nervous system is (^ttke of an elementary nature. So far as I can discover, it consists of a single cephalic ganglion, which sends off one or more minute branches to the proboscis or oral opening Organs of special sense are entirely wanting. There is nothing remarkable about the mouth. It is formed for suctorial purposes only. In form and structure it is perfectly circular, and is divided into two or three rings, which are acted upon by separate sets of circular and radial muscular fibres. The inner or middle ring, when opened out, divides into six equal parts, which turn outwards upon the inner lip, somewhat like the petals of certain flowers. The muscular layer is capable, when set in action, of producing a considerable vacuum, while the radial set will convert the innermost disc into a sphincter, closing up the oesophageal opening. The oral arrangement of the male appears to me to differ slightly. I make out a third inner divided disc, with a series of equally disposed chitinous teeth. Dr. Cobbold, in his valuable work on Entozoa, in a wood- cut drawing of the female, represents the disc I allude to, but this is an error on his part, for this is only seen in the male. Tiie vulva and uterus of the female is located unusually high up in the body, and here the male is securely attached. In this case it is the female who shows herself an imperious monogamist, for having selected a mate she compels him to cling to her body, and thus carries him about wdth her for the rest of her natural life. It has long been in dispute whether or not actual mcorporation of substances takes place between the sexes. Von Seibold taught that there is actual incorporation, but I believe this is quite a mistaken view, founded, of course, on the very intimate nature of the connection, although the same kind of joining of the sexes is seen to take place in certain of the Lepidoptera—the silkworm moth, for instance. The male organ of generation is of a very distinctive cha- racter. It consists of a Assbie se|^, of trifurcate, finger-like series of processes, and an intermediate isrijartite penis. These several parts, on passing through the vulva, have an antagonistic action to the other. I have been unable to satisfy myself of the existence