Cricetomys gambianus is a rat that lives principally in burrows, coming out at night in search of food. The design and structure of the lower respiratory system reflects its oxygen and metabolic demand which can be attributed to its habitat. A morphological and morphometric investigation of its lower respiratory system was undertaken to document the normal anatomical features and assess its morpho-functional paradigm. Specifically, an anatomical detail of the lungs and conductive airway was described, the structures being elucidated by dissection and radiography. Evaluation of dissected specimens showed that tracheal cartilages ranged from 21 to 33 rings with an average of 25.5. They exhibited a random pattern of anastomoses between adjacent rings. Transverse diameters of the principal bronchus in the male and female rats were 3.767 and 3.759 mm respectively. The right lung consisted of four lobes while the left lung was not lobed. Bronchogram revealed that lung lobation corresponded with bronchial tree division. Inter-lobar fissures were absent on the right lung except for the ventral boarder separating the cranial lobe from the caudal lobe. The entire lungs provided stability to the heart in situ, through the cardiac notch. This study also included correlation analysis of the dimensions, weights and volumes of the lower respiratory organs with the nose-rump length and body weight of 18 African giant pouched rats of both sexes. The relationship of the anatomy of the lower respiratory system of the rodent to the oxygen tension in their burrow and to their energy utilization is discussed.

SUMMARY:This study was conducted using 12 Adult African Giant Pouched rats of both sexes to compare and to see the effect of three different methods of bone preparation on the bones of the African Giant Rat (Cricetomys gambianus). Five rats were used for maceration method, three for burial method and four rats for chemical method (involving two rats each for 3% and 5% solution of Sodium Hydroxide). Chemical preparation with Sodium Hydroxide was found to be the best method in terms of time required to complete the procedure, number of bones recovered, colour of the bones and odour of the preparation. However, the chemical method has the disadvantage of dissolving and cracking the bones if the concentration used is high and prompt attention is not given to the preparation.

This study was conducted to investigate the morphological development of the Helmeted Guinea fowl (Numida meleagris) gastrointestinal tract pre-and post-hatch. Eighty seven (87) eggs were purchased from the Poultry unit of National Veterinary Research Institute (NVRI), out of which eighty one (81) were used for pre-hatch and six (6) were allowed to hatch for post hatch studies. The development was recorded daily at pre-hatch while it was observed at day 1 and 8 at posthatch. The result revealed that at day 8 of incubation a digestive tube appeared with a roundish structure in the middle of the tube. By day 10 Development of GIT of Helmeted Guinea Fowl Gosomji et al.that days 8-13 of incubation are the most critical period for the gross formation of the GIT in the guinea fowl.

ABSTRACT

Anatomy of the mystacial vibrissae in the African giant pouched rat was investigated to establish the role played by these structures in the adaptation of the rodent to its subterranean environment. Gross morphology was based on direct observation of the mystacial vibrissae with the naked eyes, while histology was based on light microscopic examination of the same structure stained with haematoxylin and eosin (H/E), Masson's trichrome (MT) and Masson-Fontana reducing method for melanin. The mystacial vibrissae were aligned in 5-6 rows on each side of the face. The length increased rostrocaudally in each row. The mean number of vibrissae was 55.29 (± 3.42). The vibrissal folliclesinus complex extended into the reticular layer of the dermis. In the proximal part of the sinus, trabeculae of connective tissues connected the internal and external dermal sheaths. The most distal part of the sinus contained blood vessels. The external dermal sheaths were thick and held in position by muscle fibres. Mean thickness of the cortex and medulla in the complex were 1.626 µm (± 0.110) and 0.775 µm (± 0.057), respectively. The thick external dermal sheaths were laden with mechanoreceptors. The thick cortex provided the needed elasticity necessary for touch and sensation. In conclusion, the well developed mystacial vibrissa in the African giant pouched rat is an important compensation for poor vision, necessary for an effective adaptation.