Some Digenetic Trematodes of Marine Fishes from the Barrier Reef and Reef Lagoon of BelizeFISCHTHAL, JACOB H.
doi: 10.1111/j.1463-6409.1978.tb00787.xpmid: N/A
A total of 200 marine fishes (36 species) from the Caribbean Sea off Belize were examined for digenetic trematodes and 163 (81.5%) harbored at least one species. Five species are described as new: Lasiotocus asymmetricus (Monorchiidae) from Haemulon flavolineatum; Stephanostomum belizense (Acanthocolpidae) from Caranx bartholomaei; Neolepidapedon belizense (Lepocreadiidae) from Sphyraena barracuda; Opecoeloides belizensis (Opecoelidae) from Priacanthus arenatus; Saturnius belizensis (Hemiuridae) from Mugil curema. 72 previously known species were identified, and all represent new geographical distribution records while many are recorded from new hosts. Their zoogeographical affinities are very strongly with the tropical western Atlantic, although some also occur in the eastern Atlantic, Mediterranean, and Indo‐Pacific regions.
Some Adaptive Features in the Respiratory System of Dineutes indicus Aubé (Coleoptera, Gyrinidae)TONAPI, GOPAL T.
doi: 10.1111/j.1463-6409.1978.tb00790.xpmid: N/A
The spiracular structure characterized with a system of snarling dense outgrowths, has been studied in order to elucidate their reinterpreted role in respiration. The tracheal anatomy has undergone modifications to subserve a secondary function of reducing the metabolic heat in the thorax—a region of relatively high metabolic activity. Tracheation is so arranged as to enable this insect to lead successfully an amphibious existence. The rate of its oxygen consumption and its capacity to remain under water with an air bubble which functions as an efficient physical gill with temperature as an important limiting factor has been studied. Attempts have been made to analyse the anatomy of the respiratory system with reference to the insect's behaviour in its environment.
The Structure and Mineralization of the Carapace of the Crab ( Cancer pagurus L.) 2. The exocuticleHEGDAHL, TROND; GUSTAVSEN, FINN; SILNESS, JOHN
doi: 10.1111/j.1463-6409.1978.tb00789.xpmid: N/A
The exocuticle of the dorsal carapace of the intermoult Cancer pagurus was studied by means of light microscopy, electron microscopy, and contact microradiography. In the exocuticle a 5‐15 μm wide highly mineralized external zone was seen where prisms were not present. The cross‐sectional shape and diameter of the prisms varied. The prisms were separated by interprismatic areas varying in width and in degree of mineralization. With increasing width of the interprismatic areas the diameter of the prisms decreased. The prism‐less external zone may be the result of complete mineralization of the prisms. The pore canals of the exocuticle were circular in cross section and present both within the prisms and within the interprismatic areas. The lamellar system of the exocuticle was built up by layers of horizontal fibrils which were interconnected by vertical or oblique fibrils. The minerals of the external prism‐less zone occurred as aggregates of crystalline matter or as large brick‐like structures. Crystal edge lengths up to 300 nm were measured. In well mineralized interprismatic areas aggregates of crystals and relatively large crystals were observed. In poorly mineralized interprismatic areas small plate‐like crystals occurred. Occasionally a prism‐less zone was seen near the exocuticle/endocuticle junction.
A Contribution to Structural Analysis of the Head of Craniate Animals 1 The orbit and its contents in 20‐22‐mm embryos of the North American actinopterygian Amia calva L., with particular reference to the evolutionary significance of an aberrant, nonocular, orbital muscle innervated by the oculomotor nerve and notes on the metameric character of the head in craniatesBJERRING, HANS C.
doi: 10.1111/j.1463-6409.1978.tb00792.xpmid: N/A
An attempt has been made to reconcile a hitherto unknown, nonocular, orbital muscle in the embryology of the North American actinopterygian fish, Amia calva L. with the basic morphological theme which pervades the cephalic division of craniate animals. It is concluded, among other things, that this somatic muscle innervated by the oculomotor nerve represents the basicranial muscle of the second, or premandibular, metamere and that it is homologous with the eye stalk in elasmobranchs as well as with the basiorbital in embryonic lampreys. Un essai est tenté pour expliquer la présence d'un muscle orbitaire non‐oculaire jusqu'alors inconnu. dans l'embryologie du poisson Actinoptérygien nord‐américain Amia calva L., à la lumière du thème morphologique fondamental qui régit la division céphalique des animaux Craniotes. II en est conclus, entre autre, que ce muscle somatiqué innerve par le nerf oculomoteur commun représente la muscle basicranien du second métamère, ou métamère prémandibulaire, et qu'il est l'homologue du pédoncule oculaire des Elasmobranches ainsi que du basiorbitaire de l'embryon des Lamproies.