The Morphological description and histological structure of olfactory organ in barn owl have been studied. The results of morphological description showed that the olfactory organ in the animal under study have pair of external nares ovale shape which lead to pair of nasal chambers which are located at the dorsal surface of head under eyes level. The chambers are conical in their shape the anterior end is narrow while the posterior end is enlarger the nasal chambers open to the oral cavity through the internal nares.      The results also showed that the nasal cavity contains three chonchae which represented by rosteral chonchae, elongated middle chonchae and the posterior nasal chonchae called olfac

The ceiling of the midbrain has a couple of optic lobes which are prominent and used as an optic center that reflex what it receives from eye retina fibers. The histology of optic tectum has been studied in Iraqi fish Barbus luteus (Heckel) . It was found that the number of optic tectum were six main strata organized from the outside to the inside as follows : the stratum marginal (SM), the stratum opticum (SO), the stratum fibrosum et griseum superficialis (SFGS), the stratum griseum central (SGC), the stratum album central (SAC), the stratum periventricular (SPV), . the tow last strata consider deep layers on the optic tectum. It was noticed that the superficial strata was the first (SM), while the thickest strata was the four (SGC), whic

  The study includes histological structure of  digestive tract of  Liza abu , Anatomical results found that the digestive tract occupied the largest part of  abdominal cavity ,  the mean gut length was (45.5) cm and relative gut length was (2.9) .  esophagus was a muscular tube length (1.5) cm , esophagus wall containing longitudinal  straight unbranched folds numbering (9) . Histological study  results found that the esophagus composed of four tunica : mucosa , submucosa , muscularis and serosa . The results found that the mucosa consists of three layers : epithelium , lamina propria and muscularis mucosa . The epithelial layer was stratified squamous epithelium thickness (139.1) µ containing

  The study current included histological structure of stomach of Liza abu , anatomical results found that stomach represent the expander non-convoluted part of gastrointestinal tract it is located between the end of the esophagus and the beginning of the intestine , the average length of stomach was (1.5) cm , composed of two parts : cardiac stomach which is represent the anterior part and be thin- walled , the other part was pyloric stomach or gizzard and the walls were thick . The internal surface of cardiac and pyloric stomach contain longitudinal folds numbering (7), folds branching to finger shape structures extend inside the lumen . Histological study showed that stomach wall composed of three main histological layers : mucos

 The study includes histological structure of  pyloric caeca , intestine and rectum of Liza abu , the results show that the pyloric caeca are non-branched fingerlings structures numbering (4) and length rate was (0.5) cm , while the intestine of Liza abu was long narrow tube composed of a number of laps , the anterior part of intestine was wider in diameter than the posterior part , the length of intestine was (32) cm , the rectum was straight tube extends from the end of posterior part of intestine to the anus.         The wall of pyloric caeca , intestine and rectum consists of main layers : mucosa , submucosa , muscularis and serosa , lining epithelium of  pyloric caeca , intestin

For the first time in Iraq, this study presented a putj;uance to ti the

main embryological development phases of the Asian catfish Silurus

triostegus .Embryological morphological illustrations and behaviour remark have been given.

It was found that eggs of this species are of Telolecithal type. Two hours after fertilization of the fi rst cleavage took place  , it became

taster until the 64 cells stage, af\erward slowed down . In 4 hours the eggs reached the morula stage while gastrula stage achieved within 9 hours.

Separation of head and tail commence at 25 hours . First, heart

pulssing was observed at 35 hourswhile blood flow started 8 hours later .

Chromatop

This study was achieved to investigate the accumulation of some heavy metals included: Cadmium, Lead and Nickel in the tissues (gill, intestine, liver, muscles and skin) of Silurus triostegus Heckel, 1843 (Siluriformes, Siluridae) and its larval stage of the nematode Contracaecum sp. (Rhabditida, Anisakidae). As well as to assess the infection patterns of Contracaecum among S. triostegus specimens which were purchased fresh from the local market in Baghdad. One hundred and nine nematodes specimens in larval stage were recovered from the fish host; the overall prevalence of Contracaecum sp. was 38.6%. The sex of the host was not significantly (P ˃ 0.05) associated with the infection of this nematode. Results showed that the ov

This study was achieved to investigate the accumulation of some heavy metals included: Cadmium, Lead and Nickel in the tissues (gill, intestine, liver, muscles and skin) of Silurus triostegus Heckel, 1843 (Siluriformes, Siluridae) and its larval stage of the nematode Contracaecum sp. (Rhabditida, Anisakidae). As well as to assess the infection patterns of Contracaecum among S. triostegus specimens which were purchased fresh from the local market in Baghdad. One hundred and nine nematodes specimens in larval stage were recovered from the fish host; the overall prevalence of Contracaecum sp. was 38.6%. The sex of the host was not significantly (P ˃ 0.05) associated with the infection of this nematode.
Results showed that the overall me