Sycon

The Porifera may be defined as an asymmetrical or radially symmetrical multicellular organism with a cellular grade of an organization without well-definite tissues and organs; exclusively aquatic; mostly marine, sedentary, solitary, or conical animals with body perforated by pores, canals, and chambers through which water flows; with one or more internal cavities lined with choanocytes; and with a characteristic skeleton made of calcareous spicules, siliceous spicules or horny fibers of spongin.

Sycon also called scypha, a genus of marine sponges of the class caldera calcareous sponges is characterized by a fingerlike body shape known as the conoid type of structure. In the conoid sponges, each finger known as a radial canal is perforated by many tiny pores through which water passes into a single central cavity. The water exits through the oscula, or a larger opening, at the tip. Water is driven through the sponge by the beating of many hairlike cilia lining the central cavity. scypha species grow to only about 2 or 3 cm in length. Scypha or sycon as formerly known is a more complex type than Leucosolenia since Leucosolenia is a primitive asconoid type with no folding in its body wall, while Scypha’s body wall is folded and therefore its spongocoel is comparatively smaller. The organization of such sponges differs greatly due to different degrees of folding in the body wall.

Sycon or scypha

Sycon is a genus of sponges that belong to the family Sycettidae and phylum Porifera. These organisms are tube-shaped, often growing up to 3 inches in height. It is usually white to cream in color and is found attached to shells and rocks. They thrive in the temperate coastal waters of the world.  These are divided into 3 different groups based on the presence or composition of spicules or spongin. Calcaria, Hexactinellida, Demospongiae.

Structure of sycon

There is a great diversity observed in the form of sponges ranging from simple to complicated entities. However, they still can be categorized as intermediate when it comes to structural diversities. It has branched cylinders that are connected at the basal end, intact to the substratum. The body is flexible though it is secured firmly. A closer look at these entities reveals the presence of many tiny Ostia or inhalant pores. The free end of every cylindrical branch has an opening at the summit known as an osculum. The wall of the sycon is lined by cells called pinacocytes.

Classification of sycon

The classification of sycon is given below:

• Kingdom: Animalia
• Phylum: Porifera
• Class: Calcarea
• Order: Heterocoela
• Family: Sycettidae
• Genus: Sycon

Phylum Porifera: The phylum includes nearly 5000 species that are known. Typically characterized by the presence of pores all through the body justifying the name Porifera, the ones who bear pores and are also referred to as sponges. Generally, they are represented by Sycon, Leucosolenia, Euplectella, Hyalmonema, etc. Based on the nature of the skeleton, Phylum Porifera is classified into three classes:

Class 1: Calcaria

Class 2: Hexactinellida

Class 3: Demospongia.

Habit and Habitat of sycon: Sycons lead a solitary/colonial life. These marine entities are found attached to the solid substrate such as shells and rocks of corals and mollusks. Various species of sponges under this genus do not tend to thrive deeper in the ocean. Sycons seem to thrive well in slow-wave action and low tides. They are found on the underside of rocks in comparatively protected regions amongst hydroids, bryozoans, and other entities. Some also grow as seaweeds.

Identifying features

• It has a vase-shaped cylindrical body measuring about 20-30 mm in length
• Each cylinder opens to the exterior by an osculum
• Body surface contains numerous pores called Ostia or incurrent pores
• Osculum is encircled by a fringe of monoaxon spicules
• Their bodies are radially symmetrical or asymmetrical

• They can regenerate their lost parts
• Needle-like spines called spicules cover their body

Canal system of sycon

Sycons exhibit a canal system which is an anatomical peculiarity, unique to them. It penetrates the body with watcher channels. The canal type precisely seen in Sycon is Syncoid Stage I type, more advanced than the asconoid canal system. The Ostia opens into a central cavity through a system of canals, the central cavity is known as spongocoel.

The body is organized into a complex network of canals and pores, which goes on to form the aquiferous or the canal system. The body wall is composed of Choanoderm, Mesenchyme and Pinacoderm.

The composition of the canal system of sycon is as follows:

• Ostia: The pores present on the body of the sycon are called Ostia. It sends the water current into the incurrent canals. It also regulates the amount of water entering the body

• Incurrent Canals: The dermal pores send water to the incurrent canal which is narrow from the inside. These are lined by pinacocytes. The inner end of the canal is closed. There is a presence of small apertures called prosopyles in between the incurrent canal and radial canal.

• Prosopyles: The prosopyles help to move the water inside the radial canal

• Radial Canals: The radial canal is lined up by choanocytes or flattened cells. These choanocytes help to move the water inside the body. These are closed externally and opened by a small aperture called apopyle

Nutrition, Respiration and Excretion in sycon

The sponges feed on micro-organisms that enter the body along with the water current. The choanocytes engulf them and pass them to the amoeboid cells situated below the choanocytes. The digestion takes place inside the amoeboid cells and assimilated products are conveyed to the various parts of the body.

Thus nutrition is holozoic and digestion is intracellular, a process comparable to that of protozoans. Some amoeboid cells often contain chlorophyll or green pigments and carry out autotrophic nutrition like green plants.

The presence of algae within the sponge body also helps in nutrition. Respiration and excretion take place by diffusion. The contractile vacuoles are recorded in the amoeboid cells of freshwater sponges which probably play an important role in osmoregulation and excretion.

Sycon Reproduction

In sycon reproduction, we observed both sexual and asexual modes.

• In asexual mode they produce buds and in some cases, it produces special structures called gemmules
• In sexual mode, the female gametes and male gametes are produced from the archaeocytes present in mesoglea. The sperm cells have long tails and can swim freely in the water current. The ova can wander in mesoglea
• The sperm cell does not enter the ova directly. But the sperm moves nearer to the egg with the assistance of the choanocyte
• The early development is seen inside the mother sponge. When the development is complete, it is moved to a radial canal and from there it emerges

Conclusion

Sycon also called scypha, a genus of marine sponges of the class caldera calcareous sponges is characterized by a fingerlike body shape known as the conoid type of structure. Sycons exhibit a canal system which is an anatomical peculiarity, unique to them. It penetrates the body with watcher channels. The body is organized into a complex network of canals and pores, which goes on to form the aquiferous or the canal system. The body wall is composed of Choanoderm, Mesenchyme and Pinacoderm.