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The sweetbread, a gland connected with the intestine of nearly all vertebrates. It is usually elongated and light-colored, and its secretion, called the pancreatic juice, is discharged, often together with the bile, into the upper part of the intestines, and is a powerful aid in digestion. See Illust. of Digestive appa…

ral arch, or Pectoral girdle (Anat.), the two or more bony or cartilaginous pieces of the vertebrate skeleton to which the fore limbs are articulated; the shoulder girdle. In man it consists of two bones, the scapula and clavicle, on each side. -- Pectorial cross (Eccl.), a cross worn on the breast by bishops and abbo…

elvic arch, or Pelvic girdle (Anat.), the two or more bony or cartilaginous pieces of the vertebrate skeleton to which the hind limbs are articulated. When fully ossified, the arch usually consists of three principal bones on each side, the ilium, ischium, and pubis, which are often closely united in the adult, forming…

The entire covering of an invertebrate animal, as echinoderm or coelenterate; the integument.

The membrane surrounding the mouth of an invertebrate animal.

The distal segment of the hind limb of vertebrates, including the tarsus and foot.

A group of invertebrates including the Tunicata and Enteropneusta. -- Pha*ryn`gop*neus"tal, a.

uth and the esophagus. It has one or two external openings through the nose in the higher vertebrates, and lateral branchial openings in fishes and some amphibias.

ne cone. Pineal gland (Anat.), a glandlike body in the roof of the third ventricle of the vertebrate brain; -- called also pineal body, epiphysis, conarium. In some animals it is connected with a rudimentary eye, the so-called pineal eye, and in other animals it is supposed to be the remnant of a dorsal median eye.…

A chitinous structure which supports the gill in some invertebrates.

behind, or on the caudal or posterior (that is, ulnar or fibular) side of, the axis of a vertebrate limb.

k or trace (Anat.), an opaque and thickened band where the mesoblast first appears in the vertebrate blastoderm.

r forming, the front of the head. Procephalic lobe (Zoöl.), that part of the head of an invertebrate animal which is in front of the mouth.

One of the primitive masses, or segments, into which the mesoblast of the vertebrate embryo breaks up on either side of the anterior part of the notochord; a mesoblastic, or protovertebral, somite. See Illust. of Ectoderm.

Pseudhæmal fluid, the circulatory fluid, or blood, of annelids, analogous to the blood of vertebrates. It is often red, but is sometimes green or colorless. -- Pseudhæmal vessels, the blood vessels of annelids.

Any contractile vessel of invertebrates which is not of the nature of a real heart, especially one of those pertaining to the excretory system.

esponds to the inner plate of the pterygoid process of the human skull, but which, in all vertebrates below mammals, is not connected with the posterior nares, but serves to connect the palatine bones with the point of suspension of the lower jaw. -- Pterygoid process (Anat.), a process projecting downward from either…

A posterior division of the stomach in some invertebrates.

ey. Quadrate bone (Anat.), a bone between the base of the lower jaw and the skull in most vertebrates below the mammals. In reptiles and birds it articulates the lower jaw with the skull; in mammals it is represented by the malleus or incus.

An extensive artificial group of invertebrates, having all the parts arranged radially around the vertical axis of the body, and the various organs repeated symmetrically in each ray or spheromere.