A, Lateral region of the cephalic plate to which the first pair of appendages are articulated.
Cephalic or first prosomatic 2, Second do.
The development of these organs, which in the Protonemertine are but grooves in the epidermis, not far removed from the similar cephalic slits of many Turbellaria, reaches its height in Drepanophorus.
Four pairs of appendages besides these are seen to belong to the cephalic tergum.
In the Orthorrhapha, in the pupae of which the appendages of the perfect insect are usually visible, the pupa-case generally splits in a straight line down the back near the cephalic end; in front of this longitudinal cleft there may be a small transverse one, the two together forming a T-shaped fissure.
Anterior area of the mantle-skirt over-hanging the head (cephalic hood).
- Anterior portion of the same and opening on the right Limpet, with the overhanging cephalic shoulder, so to speak, of hood removed.
Below the surface these walls are excavated with blood-vessels, so that the sac is practically a series of blood-vessels covered with renal epithelium, and forming 6 Cephalic tentacle.
They are found one on each cephalic tentacle, and are simply minute open pits or depressions of the epidermis, the epidermic cells lining them being pigmented and connected with nerves (compare fig.
An epipodial ridge on each side of the foot and cephalic expansions between the tentacles often present.
Shell with very low spire, without umbilicus, internal partitions frequently absorbed; a single ctenidium; a cephalic penis present.
T, Cephalic tentacle.
(Lankester.) a, Cephalic tentacle.
The head is seen in front resting on the foot and carrying a median non-retractile snout or rostrum, and a pair of cephalic tentacles at the base of each of which is an eye.
I, Under surface of the mantle c, Cephalic eye.
Skirt forming the roof of the d, Cephalic tentacle.
D, Proand meso-podium; to the right b, Cephalic tentacles.
B, Cephalic tentacle.
Dv, Velar area or cephalic dome.
N, Dorsal surface overhung by Cephalic tentacles.
The Heteropoda are further remarkable for the high development of their cephalic eyes, and for the typical character of their osphradium (Spengel's olfactory organ).
Oc, Cephalic eye.
Shell flattened; no cephalic tentacles.
Shell depressed, with rounded aperture; cephalic tentacles long.
Shell spiral; four cephalic tentacles; eyes absent; two pedal appendages.
34.-Female Janthina, with egg-float (a) attached to the foot; b, egg-capsules; c, ctenidium (gill-plume); d, cephalic tentacles.
B, Cephalic tentacles.
The detorted visceral commissure shows a tendency to the concentration of all its elements round the oesophagus, so that except in the Bullomorpha and in Aplysia the whole nervous system is aggregated in the cephalic region, either dorsally or ventrally.
It carries two pairs of cephalic tentacles and a pair of sessile eyes.
M, Mantle-flap reflected over the 0, Posterior cephalic tentacles.
O, The cephalic tentacles.
That any partial fusion of originally distinct chitinous plates takes place in the cephalic shield of Trilobites, comparable to the partial fusion of bony pieces by suture in Vertebrata, is a suggestion contrary to fact.
They are the head slits cephalic fissures, " Kopfspalten ") so characteristic of this subdivision (figs.
(From Burger.) i, Opening of proboscis; 2, cephalic glands running to frontal organ; 3, dorsal commissure of brain; 4, cerebral organ; 5, upper dorsal nerve; 6, under dorsal nerve; 7, rhynchocoelic blood-vessel; 8, fore-gut; 9, rhynchocoel; to, nerve to proboscis; 11, proboscis; 12, genital sac; 13, genital pore; 14, mid-gut; 15, circular nerves; 16, pore of excretory system; 17, lateral organ; 18, excretory canal; 19, lateral vessel; 20,.
18, 5) belonging to the maxillular (or superlingual) segment, thus establishing seven sets of cephalic ganglia, and supporting his view as to the composition of the head.
The brain innervates the eyes and feelers, and must be regarded as a " syncerebrum " representing the ganglia of the three foremost limb-bearing somites united with the primitive cephalic lobes.
Karl Semper has shown that these slugs have, in addition to the usual pair of cephalic eyes, a number of eyes developed upon the dorsal integument.
Curiously enough, however, they differ from the cephalic Molluscan eye in the fact that, as in the vertebrate eye, the filaments of the optic nerve penetrate the retina, and are connected with the re surfaces of the nerve-end cells nearer the lens instead of with the opposite end.
Hickson and others, that in the bivalves Pecten and Spondylus, which also have eyes upon the mantle quite distinct from typical cephalic eyes, there is the same relationship as in Oncidiidae of the optic nerve to the retinal cells.
(After Cuvier.) t, Anterior cephalic tentacles.
A, mouth; b, cephalic tentacle; h, gill (ctenidium).
(Lankester.) Anterior cephalic tentacle.