: The circulus arteriosus cerebri of the porcupine was investigated in this study. Five porcupines were used. Coloured latex was given from the left ventricles of three and from the communis carotid artery of two porcupines. The circulus arteriosus cerebri was examined after dissection was done. The basilar artery was formed by a merge of the right and left vertebral artery. The caudal communicans artery which was the caudal part of circulus arteriosus cerebri was formed by the basilar artery on crus cerebri. From caudal to cranial, the branches originating from the basilar artery and circulus arteriosus cerebri to cerebrum and cerebellum were as follows: caudal cerebelli artery, media cerebelli artery, rostral cerebelli artery, caudal choroidea artery, artery which extended to the mesencephalon, caudal cerebral artery, internal ophthalmic artery, rostral choroidea artery, media cerebral artery, rami striati and rostral cerebral artery. The rostral cerebral artery dexter and sinister joined to each other by the rostral communicans artery, forming the circulus arteriosus cerebri. It was determined that the internal carotid artery did not participate in the formation of circulus arteriosus cerebri and the arterial blood to the circulus arteriosus cerebri of porcupine is provided via the basilar artery only.

The aim of this study was to investigate the axial skeleton of two porcupines (Hystrix cristata). The important features of the skull, observed in this study are as follows: The zygomatic process of frontal bone (os frontal) was found to be rudimentary, and the infraorbital foramen (for. infraorbitale) was very large. The zygomatic bone (os zygomaticum) has two processes (frontal and temporal) and the zygomatic arch (arcus zygomaticum) was composed of three bones. The dental formulae were 2 (I 1/1, C 0/0, P 1/1, M 3/3) = 20. The angular process (Proc. angularis) of mandible is well developed. The vertebral formula was found as C7, T15, L4, S4, Ca12. All of cervical vertebrae had the transverse foramen (for. transversarium). The first eleven spinous processes (proc. spinosus) of thoracic vertebrae were caudally-sloped, the twelfth as the anticlin vertebrae and the last three were directed cranially. Hemal arches (or ossa arcus hemalis) were presented as separate bones which articulate with the ventral surfaces of the caudal ends of the bodies of the second, third and fourth caudal vertebrae.

The anatomy of aortic arch in porcupine was studied. Angiography was applied to each of the three adult porcupines (two males, one female) following the injection of latex from the abdominal aorta for the examination of aortic arch. The results indicated that three arteries arose from aortic arch in porcupine. These were truncus brachiocephalicus, arteria carotis communis sinistra and arteria subclavia sinistra. The truncus brachiocephalicus in porcupine yielded arteria subclavia dextra and arteria carotis communis dextra. Truncus bicaroticus was absent. The origin of truncus costocervicalis (right) and arteria vertebralis (right) arose from a common root. Left or right axillary arteries seemed to be a continuation of subclavian arteries. The results of this study may contribute to the data in this area of science.

The light and scanning electron microscopic structure of the filiform lingual papillae was studied in five adult porcupine (three males and two females). The tongue was characterised by a round tip, a rostral median sulcus and a deep lingual fossa which was situated just rostral to a prominent inter-molar eminence corresponding to a torus linguae. The filiform papillae were curved, enclosed a large connective tissue core and were separated by wide inter-papillary zones covered by a thick epithelium. Most filiform papillae had a cylindrical shape, but the rostral and central parts of the tongue contained a number of flat, comb-shaped papillae with rounded tips.

ABSTRACT:In this study, the circulus arteriosus cerebri of the ground squirrel (Spermophilus citellus) was investigated. Five ground squirrels were used as subjects. Coloured latex was injected from the left ventriculi of the hearts of all the squirrels. When the vertebral arteries of two of the animals were ligatured, it was found that there was no internal carotid artery. After careful dissection, the circulus arteriosus cerebri (the circle of Willis) was investigated. The right and left vertebral arteries gave rise to the caudal cerebellar artery before forming the basilar artery. The basilar artery formed the caudal communicans artery that was the caudal part of the circulus arteriosus cerebri on the pontocrural groove (sulcus pontocruralis). The caudal, medial, rostral cerebellar, the common root formed by the caudal cerebral and choroid arteries, the rostral choroid, the rostral and medial cerebral arteries arose from the vertebral, basilar and caudal communicans arteries and dispersed to the cerebrum and cerebellum from caudal to cranial. The termination and the branches of the rostral cerebral artery in ground squirrels varied. It was observed that the internal carotid artery does not supply the circulus arteriosus cerebri in ground squirrels. Keywords: morphology; circulus arteriosus cerebri; brain; ground squirrel (Spermophilus citellus)The rodents (Rodentia) which are the widest order of placental mammals, comprise more than half of all described mammals. The ground squirrels (Spermophilus citellus) are representatives of the Sciuridae family that constitutes a group of the order Rodentia (Karol, 1963;Weichert, 1970;Kuru, 1987;Demirsoy, 1992).There have been many investigations on the vascularisation of the arteries which supply blood to the brain. Studies have been carried out in rats (Brown, 1966;Green, 1968), rats and mice (Firbas et al., 1973), mouse (Cook, 1965;Wiland, 1974;Szczurkowski et al., 2007), Guinea pigs (Ocal and Ozer, 1992), Guinea pigs and rabbits (Popesko et al., 1990), rabbits (Brehmer and Beleites, 1988), dogs (Miller et al., 1964), cats (McClure et al., 1973), porcupine (Aydin et al., 2005), Red squirrels (Aydin, 2008), Mongolian gerbils (Klachinka et al., 2008) and mole-rats . According to our knowledge there are no investigations on the circulus arteriosus cerebri of the ground squirrel (Spermophilus citellus) and this is the first study on this subject in ground squirrels.The purpose of this study was to document arteries that constitute the circulus arteriosus cerebri in the ground squirrel (Spermophilus citellus). MATERIAL AND METHODSFive adult ground squirrels, trapped by farmers, were used. After they were anaesthetized with penthathol (6 ml/kg), the cavum thoracis of all animals were opened and a 5 mm diameter, 7 cm long plastic pipe was placed into the left cardiac ventricle. The arterial blood was drained and red coloured latex was injected into the left ventriculi through this pipe. To see whether the internal carotid artery existed, the right and left vertebral arter...