In a few cases the radialia correspond segmentally with the neural and haemal arches (living Dipnoans, Pleuracanthus tail region) and this suggests that they represent morphologically prolongations of the neural and haemal spines.
In correlation with the flattening of the body of the fish from side to side the arches are commonly prolonged into elongated neural or haemal spines.
The haemal spines of the turned-up tip of the tail are flattened (hypural bones) and serve to support the caudal fin rays.
The ventral arcualia become, in the tail region only, also incorporated in complete arches--the haemal arches.
The dorsals have short transverse processes and neural spine, the anterior and middle ones (those with a haemal spine or carina) having a large anterior pneumatic foramen between the nib-facet, the foramen being triangular in shape.
In the dorsals there is usually no anterior pneumatic foramen till the fourth (or the last with a distinct haemal carina), this foramen being situated on the line of the anterior border of the rib-facet.
Transverse section through the tail of an embryo of stage P to shew the coexistence of the rib-process and haemal arches in the first few sections behind the point where the latter appear.
Through the vertebral region, shewing the neural and haemal arches, the notochordal sheath, &c.
Below in the vertebrae of the posterior half of the body the haemapophyses (69) unite to form the haemal spine (70), and through the haemal canal thus formed passes a great artery.
The vertebrae having haemal as well as neural spines are known as caudal vertebrae, and occupy the posterior part of the body, usually that behind the attachment of the anal fin (78).
Column notochordal, showing no traces of centra; well-marked neural and haemal elements.
This state of affairs has no antecedent improbability about it, since in the Vertebrata the coelom is unquestionably confluent with the haemal system through the lymphatic vessels.
This is the vascular or haemal system (formerly and unnecessarily termed pseudhaemal).
Their lower end supports a short cartilaginous membrane, closing the haemal arch, which is attached to the broad and stiff abdominal scute.
They have rather longer bodies than common rabbits), a haemal spine was moderately well developed on the under side of the twelfth dorsal vertebra, and I have seen this in no other specimen.
They are united with each other by a delicate layer of tissue, and constitute the substance in which the neural and haemal arches subsequently become differentiated.
The haemal arches are formed from the haemal ridge in precisely the same way as the neural arches, but interhaemal intercalated pieces are often present.
In the region of the tail the haemal arches are continued into ventral processes which meet below, enclosing the aorta and caudal veins.
Since primitively the postanal gut was placed between the aorta and the caudal vein, the haemal arches potentially invest a caudal section of the body cavity.
In Acipenser and other cartilaginous Ganoids the haemal and neural arches are formed as in Elasmobranchii, and rest upon the outer sheath of the notochord.
The ventral haemal arches of these fishes are therefore clearly in no part formed by the ribs.
The haemal processes belonging to it are represented by two cartilaginous masses, which subsequently ossify, forming the hypural bones, and supporting the primary fin rays of the tail (fig.
They may be attached either to the haemal (Pisces) or neural (Amphibia and Amniota) arches.
Preservation is poorest in scales along the line of the neural and haemal arches; therefore lateral line scales are rarely preserved.
All are of the coelacanth type, having Y-shaped neural and haemal arches, without centra.
Counts of 10 and 16 haemal arches were obtained in two of the specimens.
Teleostei, and we have found that the modified haemal arches of this part support a few fin-rays, though a still smaller number than in Cnidoglanis.
As these rings are formed originally by the spreading of the cartilage from the primitive neural and haemal processes, the intervertebral cartilages are clearly derived from the neural and haemal arches.
Are the haemal arches, the ventral parts of which are thus formed by the coalescence of the ribs, homologous with the haemal arches in Elasmobranchii?
In the region of the tail-fin the haemal arches supporting the caudal fin-rays are very much enlarged.
The presence or absence of fin-rays in the tail-fin supported by haemal arches may be used in deciding whether apparently diphycercal tail-fins are aborted or primitive.
In the case of a few more vertebrae the haemal processes have united into an arch, and the spinous processes of the arches in the region of the caudal fin have grown considerably in length.
The vertebrae are wholly formed of a very cellular osseous tissue, in which a distinction between the bases of the neural and haemal processes and the remainder of the vertebra is not recognizable.
Each succeeding pair of haemal arches becomes larger than the one in front, each arch finally meeting its fellow below the caudal vein, thus forming a completely closed haemal canal.
The anterior haemal arches are much larger than the corresponding neural arches, but when followed back they gradually decrease in size, till at about the twenty-fourth caudal vertebra they are nearly as small as the neural arches.
Both neural and haemal arches are ossified continuously with the centra.
The neural and haemal arches and spines are cartilaginous and interbasalia (intercalary pieces) are present.
The ribs are homologous with the distal parts of the haemal arches of the caudal vertebrae.
The notochord is persistent and unconstricted, its sheath is membranous, but cartilaginous neural and haemalarches are developed.
All the caudal vertebrae except the first have also a haemal arch, which is very similar to the neural arch, and is drawn out into a haemal spine quite similar to the neural spine.
The notochord is unconstricted, but the neural and haemal arches are well-developed, and the neural spines are long and slender.
In Dipnoi these interspinous bones articulate with the neural and haemal spines.
The spinal column of fishes is divisible into only two regions, a caudal region in which the haemalarches or ribs meet one another ventrally, and a precaudal region in which they do not meet.
Further back at about vertebra 37, the two halves of the haemal arch project downwards and meet forming a complete arch.
In the tail region they are not differentiated from the two halves of the ventral arch, which meet in the middle line, and are prolonged into a haemal spine.
Intercalary pieces (interdorsalia) occur between the neural arches, and similar pieces (interventralia) between the haemal arches.
There are also a number of cartilaginous pieces derived from the skeletogenous layer which are arranged in two series, a dorsal series forming the neural arches and a ventral series forming the haemal arches.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "haemal" in a variety of sentences. We hope that you will now be able to make sentences using this word.
