A multidisciplinary investigation of the hemocytogenic nature of the white bodies of the ommastrephid Illex illecebrosus (Lesueur, 1821) (Cephalopoda: coleoidea)

Johnson, Florence Elizabeth Way (1984) A multidisciplinary investigation of the hemocytogenic nature of the white bodies of the ommastrephid Illex illecebrosus (Lesueur, 1821) (Cephalopoda: coleoidea). Doctoral (PhD) thesis, Memorial University of Newfoundland.

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Abstract

The present study extends previous descriptions of the white body of cephalopods by providing new information with regard to (1) morphometry, (2) gross anatomy, (3) microscopic anatomy, (4), vasculature, and (5) immunology of the white bodies within Illex illecebrosus. -- The white bodies of I. illecebrosus are paired multilobular organs; one attached to the medial surface of each eye. The multilobate configuration of each white body is related to the compartmentalized nature of the optic sinus that envelops the white body. -- Presumably, each white body is located upon the medial surface of a squid's eye to affect access of its products to the optic sinus and, hence, the general circulation. Hemooscula provide the means whereby this may be accomplished. These portals, the hemooscula, are herein described for the first time. -- In a squid of a given size, the white body (or particular parts of same) is smaller in the male than it is in the female. The length of the subganglionic process is probably one of the first morphometric characteristics of a white body to be established. -- Microscopic structure of white bodies of illecebrosus is similar to that of other species of cephalopod molluscs. The internal fibrous network of a white body together with the outer capsule form a framework for the internal tissue and vasculature. The tissue of the white body is arranged into repetitious, morphological units or groupings of cells. The individual components of the latter can be identified on the basis of their nuclear appearance. -- Four variations of white body cells are presented comprising a developmental series that produces the circulating hemocytes. These perceived variations (I through 4) can best be defined on the basis of differences in nuclear morphology. Earlier workers have attempted to define developmental stages for circulating cells of other cephalopods and a range of invertebrates based on measurements of the nucleus or the presence of cytoplasmic inclusions and have failed to achieve clarity or consistency. The fourth variation in the series, here presented for the first time, is presumably the final developmental stage prior to the circulating hemocytes, although Variation 3 may also be liberated successfully into the circulating blood. -- The white bodies of I. illecebrosus are well vascularized. Blood flows to a white body by way of the anterior and posterior ophthalmic arteries; passes through its tissue via small vessels, sinuli and hemal spaces; and eventually leaves the tissue to enter the enveloping optic sinus by way of the hemooscula; from the optical sinus, entering the venous circulation via the anterior vena cava. -- Based upon immunological characteristics ascertained during studies of unabsorbed and absorbed rabbit antiserum, the possibility of hemocytes being derived from the white body is very high. -- The information compiled within this thesis provides strong evidence in favor of the hypothesis that the white bodies are the site of hemocytogenesis, as has been earlier suggested on less valid grounds.

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