Do gastropods have a visceral mass?
gastropods. The visceral hump, or visceral mass, of gastropods is always contained within the shell; it generally holds the bulk of the digestive, reproductive, excretory, and respiratory systems. A significant part of the visceral hump consists of the mantle, or pallial, cavity.
What is meant by visceral mass?
(noun) the soft, non-muscular metabolic region of the mollusc that contains the body organs.
What is visceral mass in Mollusca?
visceral mass: the soft, non-muscular metabolic region of the mollusc that contains the body organs. mantle: the body wall of a mollusc, from which the shell is secreted.
Do all mollusks have a visceral mass?
All mollusks have a visceral mass, a mantle, and a foot. The visceral mass contains the digestive, excretory, and reproductive organs.
Where is the clam’s heart located?
Where is the clams heart located? The heart is between the intestines & the Anterior and posterior muscles.
Do all molluscs have eyes?
Molluscs have eyes of all levels of complexity, from the pit eyes of many gastropods, to the pinhole eyes of the Nautilus, to the lensed eyes of the other cephalopods. Compound eyes are present in some bivalves, and reflective ‘mirrors’ have been innovated by other lineages such as scallops.
What protects the visceral mass?
The mantle covers the visceral mass and is itself covered by the shell. The mantle cavity is usually found in the posterior end of the animal and is formed between the mantle and the visceral mass.
What is visceral in biology?
In biology, the word viscera refers to the large internal organs in the body cavity, especially in the abdominal cavity.
What is torsion in molluscs?
Torsion is a gastropod synapomorphy which occurs in all gastropods during larval development. Torsion is the rotation of the visceral mass, mantle, and shell 180˚ with respect to the head and foot of the gastropod. This rotation brings the mantle cavity and the anus to an anterior position above the head.
When is the Pope entitled to use the pallium?
The use of the pallium is reserved to the pope and archbishops who are metropolitans, but the latter may not use it until it is conferred upon them by the pope, normally at the celebration of the Feast of Saints Peter and Paul in June.
Can a non-metropolitan bishop wear the pallium?
No other bishops, even non-metropolitan archbishops or retired metropolitans, are allowed to wear the pallium unless they have special permission. An explicit exception is made for the rarely realised scenario in which a person not yet a bishop is elected pope, in which case the bishop ordaining the new pope wears the pallium during the ceremony.
What did the pallium of the sixth century look like?
The pallium of the sixth century was a long, moderately wide, white band of wool, ornamented at its extremity with a black or red cross, and finished off with tassels; it was draped around the neck, shoulders, and breast in such a manner that it formed a V in front, and the ends hung down from the left shoulder, one in front and one behind.
When did a metropolitan have to receive the pallium?
Under the 1917 Code of Canon Law, a metropolitan had to receive the pallium before exercising his office in his ecclesiastical province, even if he was previously metropolitan elsewhere, but these restrictions were absent in the revised 1983 Code of Canon Law.