The Secondary Blood Vessel System of Segmental Arteries and Dorsal Aorta in Blennius pavo and Zosterisessor ophiocephalus. Histology, Fine Structure and SEM of Vascular Corrosion Casts.

The secondary blood vessel system of the segmental arteries and of the dorsal aorta of the teleost fish Blennius pavo and Zosterisessor ophiocephalus are examined by light microscopy, transmission electron microscopy and by scanning electron microscopy of appropriately processed tissue and of vascular corrosion casts. Dorsal, lateral and ventral segmental arteries and the caudal portions of the dorsal aorta have a secondary vessel system. The secondary vessels are formed by capillaries which arise from the proximal portions of the segmental arteries and from the caudal parts of the dorsal aorta. In Z. ophiocephalus these capillaries are strongly dilated at their origin, in B. pavo they are less dilated, but more intensively coiled. The secondary vessels establish veins which run parallel to the corresponding primary arteries. At the ultrastructural level the secondary vessels consist of a thin endothelium and a longitudinal and a transversal orientated layer of collagen fibres. Secondary veins lack a basal membrane. A possible function of the secondary vessel system of B. pavo and Z. ophiocephalus as a modified drainage system is discussed

Vascularization of Male Gonads in Blennius pavo (Teleostei, Blenniidae) as Revealed by Scanning Electron Microscopy of Vascular Corrosion Casts

The vascular architecture of male gonads of Blennius pavo is studied by scanning electron microscopy of vascular corrosion casts. Arterial supply to the gonads is by a branch of the first ventral segmental artery of the tail. From the surface of the gonads, this vessel gives rise to branches which supply testes, spermatic ducts, testicular glands, blind pouches, urogenital sinus and urogenital papilla. The testis has a rope-ladder-like capillary network around the seminiferous tubules, while in the testicular gland the capillary network is irregular in form. The spermatic ducts are found to have an exterior capillary network located in the compact connective tissue layer and an interior one, lying subepithelially. Urogenital sinus and urogenital papilla show a multilayered capillary network. Angioarchitecture in mature and immature gonads does not differ

Odabir ukrasa kod male rakovice Maja crispata Risso 1827 (Brachyura, Majidae)

Decoration preferences, position, structure and morphology of the hooked setae were questions addressed in this study. Data were collected through the use of a scanning electron microscope. The location of the hooked setae on the exoskeleton was mapped. Spider crabs (family Majidae) often decorate themselves. They put pieces of marine organisms among the hooked setae of the exoskeleton. The decoration might serve as protection from visual predators. M. crispata is an opportunist that uses several algae, based on the abundance of the available algae and the morphological structure. M. crispata also is a generalist: it attempts to look less like a crab in order to become invisible to its visual predators.U ovom radu obrađuju se pitanja odabira dekoracija, položaja, strukture i morfologije kukastih seta. Podaci su prikupljeni pomoću skenirajućeg elektronskog mikroskopa. Ucrtavan je položaj kukastih seta na egzoskeletu. Rakovice (porodica Majidae) se često ukrašuju. Među kukaste sete na svom egzoskeletu stavljaju dijelove morskih organizama. Ta dekoracija može služiti kao zaštita od vizualnih predatora. M. crispata je oportunist koji koristi nekoliko algi, ovisno o brojnosti dostupnih algi i morfološkoj strukturi. M. crispata je također generalist: pokušava što manje izgledati kao rak da bi tako postala što manje vidljiva svojim vizualnim predatorima

The Vascularization of the Skin of the Atlantic Hagfish, Myxine glutinosa L. as Revealed by Scanning Electron Microscopy of Vascular Corrosion Casts

The vascularization of three different (A, B, C) skin regions (from the level of the heart to the cloaca including dorsal, lateral and ventral skin areas) of the Atlantic hagfish, Myxine glutinosa L. was studied by scanning electron microscopy of vascular corrosion casts. Vessel variables were measured either from semithin sections (diameters) or from vascular corrosion casts (diameters, lengths) and total blood capacities as well as vessel surfaces per unit skin area (mm2) were calculated. There are no significant differences in the number of subepidermal capillary meshes (ranging from 164 to 185 meshes per micrograph) in areas A, B or C nor in vessel lengths. The average vessel length per mm2 is 32 mm. Assuming an average diameter of 22.3 μm these vessels have an average surface of 2.24 mm2 and a volume of 12.5 nanoliters (nl). In contrary weighing two pieces ( 5 mm times 5 mm in size) of the whole skin vascular bed - knowing the density of the casting medium -results in only one fifth of that volume. Overestimation of vessel lengths and diameters by measuring casted structures from micrographs on the one hand and inaccuracies in weighing or dissection of casted skin pieces on the other hand are discussed as sources of observed differences

Observations on the agonistic behaviour of Lepadogaster lepadogaster purpurea (Pisces: Gobiesocidae)

Agonistic behaviour of captive Lepadogaster lepadogaster purpurea was described, forming the first record of such behaviour in the family Gobiesocidae. Both male and female engaged in similar behaviours. The agonistic interactions were related mainly to the control of shelter sites and larger fish tended to chase away and take over the shelter of smaller fish