Dilly Herring (7 results)

The general morphology and ultrastructure of the epidermal and arm tip photophores of H. macrohista have been compared. Both types of photophore have similar structures and the photocytes of each are characterized by dense aggregations of endoplasmic reticulum. The filter region of the epidermal photophores contains protoporphyrin. 12 pp., 1 fig., 4 pls, gr. 8.

There has previously been some dispute over the source of the light of Heteroteuthis. Light and electron microscopy have shown that there are no bacteria in the cavity of the luminous gland, but rather a population of spherical vesicles of varying size and content, surrounded by dense interstitial material. The contents are secreted by the cells surrounding the gland via a microvillous brush border that contains cilia. The gland is surrounded by a reflector layer made up of iridophores, whose structure differs considerably in the proximal, lateral and cap regions. The ink sac contains masses of spherical dense granules and its wall cells have many microvilli extending amongst these granules. 13 pp., 2 figs, 5 pls, gr. 8.

London, 1974. estratto pp. 81/100 con 6 tav. e 2 fig. - !! ATTENZIONE !!: Con il termine estratto (o stralcio) intendiamo riferirci ad un fascicolo contenente un articolo, completo in se, sia che esso sia stato stampato a parte utilizzando la stessa composizione sia che provenga direttamente da una rivista. Le pagine sono indicate come "da/a", ad esempio: 229/231 significa che il testo è composto da tre pagine. Quando la rivista di provenienza non viene indicata é perché ci è sconosciuta. - !! ATTENTION !!: : NOT A BOOK : ?extract? or ?excerpt? means simply a few pages, original nonetheless, printed in a magazine. Pages are indicated as in "from? ?to", for example: 229/231 means the text comprises three pages (229, 230 and 231). If the magazine that contained the pages is not mentioned, it is because it is unknown to us.

Pyroteuthis margaritifera has morphologically distinctive photophores on the tentacles, eyeball and in the mantle cavity. The photogenic tissue in each photophore is identical, has a blue-green fluorescence and luminesces on treatment with dilute hydrogen peroxide. The photocytes frequently contain organized fibrillar material akin to that in the photocytes of certain other cephalopods. Several different types of blood vessel are present among the photocytes, including some, apparently restricted to the photophores, with a microvillous endothelium. Haemocyanin is present not only within identifiable blood vessels but also in some intercellular spaces. On the basis of their characteristic optical systems the photophores can be separated into three types: (1) tentacular; (2) ocular and anal; (3) branchial and median abdominal. The tentacular photophores have collagenous reflector and light guide systems and the median ones are double organs. The ocular and anal organs do not have collagenous optical structures but an elaborate variety of reflective iridosomes. Those in the aperture of the photophores appear to act as interference filters. The branchial and abdominal organs have iridosomes as the major reflective tissue but collagenous fibrils function as light guides in the aperture of these organs and their emission is diffuse rather than collimated. 18 pp., 2 figs, 7 pls, gr. 8.

Examples of the ocular, digestive gland and brachial end-organ photophores of specimens from all 13 cranchiid genera are described. The cranchiine and taoniine subgroups have different ocular photophore morphologies, but very similar brachial end-organs in adult females. Most taoniines have ocular photophores that contain large numbers of crystalloids, but these are lacking in Helicocranchia and Sandalops. There are no crystalloids in cranchiine ocular photophores, in taoniine digestive gland photophores (Megalocranchia) or in the brachial end-organs of both groups. The cranchiine Leachia atlantica uniquely has one group of photocytes that contain aggregates with some similarities to the taoniine crystalloids. The end-organs of mature females have a glandular structure; the deciduous photocytes are structurally different from those present in the ocular or digestive gland photophores. The reflectors of Sandalops and Megalocranchia contain unusual arrangements of iridosomal platelets. End-organs lack any reflective structures. The comparative anatomy of the photophores supports the separation of the cranchiine and taoniine groups but the ultrastructural detail provides common links between the two. 18 pp., 10 figs, 4.

The ocular photophore of Bathothauma emits light. The presumed photogenic tissue is cellular and contains a mass of highly organized crystalloids. One of its surface abuts against a fibrous system that probably acts as a light guide. The rest of the organ is surrounded by a pigment screen of modified iridophores. 20 pp., 2 figs, 6 pls, gr. 8.

Females and juveniles of Selenoteuthis scintillans have photophores of several structural types, distributed on the tentacles and eyeballs, and within the mantle cavity and tail. Three distinct photophore types can be recognized on the basis of their accessory structures, though their photocytes are identical. The tail and some tentacular photophores (Type 1) lack any accessory optical structures; other tentacular and abdominal photophores (Type 2) have collagenous diffusing fibres; the anal and ocular photophores (Type 3) have a variety of iridosomes but no collagen. The distal tentacular organ is a double structure composed of a unit each of Type 1 and Type 2. Ocular photophores 1 and 5 are also double structures, composed of two Type 3 units. The photophores closely resemble in structure those of Lycoteuthis diadema. The photocytes have a marked fluorescence and luminesce on treatment with dilute hydrogen peroxide. The bio-luminescence intensity of the tail organ may be modified by chromatophore movements and has a blue-green spectral emission. The photophores of juvenile Lampadioteuthis megaleia are similar in structure to those of Selenoteuthis but somewhat less complex. A comparison between the morphology of the photophores of lycoteuthid and enoploteuthid squids emphasizes the close similarity between the two families. At the ultrastructural level, certain photophores of both families have very characteristic microvillous blood vessels associated with the photocytes. 23 pp., 3 figs, 11 pls, gr. 8.