All the components of the Weeverfish venom gland come together to form a very effective defence mechanism. Although this project has described these components in detail. The way in which all this components work together resulting in the efficient delivery of the toxin is as yet unexplained. The Weeverfish has been known to actively strike at other organisms in order to do this a variety of processes have to be initiated. By elevating the opercular plate the weever exposes the opercular spine and therefore increasing the chances of the other organism being "stung".

One possible method of venom delivery is the opercular spine is first raised to increase the amount of spine exposed. This is achieved by the interaction of two muscles attached to the opercular plate (fig 14). These two muscles work antagonistically (one raising the spine the other lowering the spine). As the spine is raised the outer membrane is pulled down the shaft of the spine. This is due to the membrane being non-elastic which exposes the spine tip. The amount of tip exposed depends on the angle at which the opercular is raised from the body.

The outer Membrane moving down the shaft results in the build up of pressure directed onto the glandular mass, pressing the cells into the basal groove ( when relaxed the venom gland extends outside of the basal groove) . The resultant pressure forces some of the cells into the basal groove. The resultant pressure bursts some of the cells forcing their cell contents up along the spinal groove. Glandular cells that are forced up the spine still intact are burst as they near the spine tip, due to the narrowing of the groove. The toxin and other cellular contents are passed to the outside.

This could be of advantage to the weever if other organisms could detect the venom in the water and be repelled by it, therefore leaving the weever alone, eliminating the risk of damage to the weever if the predator attacked. This idea of the weever being able to give a chemical as well as a visual warning (exposure of the spines, dorsal spines especially as they have a black membrane) is purely speculative and requires further investigation.

Although actual venom excretion wasn't seen. The action of another body pressing onto the opercular spine and surrounding membrane would have a similar effect, resulting in the venom being passed through the spinal groove into the puncture wound made by the tip of the spine and into the host animal.

The spine is very important as the toxin is most effective when injected intravenously and has very different effects depending on how the venom enters the body.

There is no evidence in the literature concerning the effects of the toxin introduced into the body by other means, absorption by the skin etc. The site of the venom injection is also important due to the venom activity on various organs within the body.

In contrast to Skies (1962) suggestion that the cells simply burst releasing their contents into the spinal groove, Another possible method of venom injection involves the cells remaining intact actively secreting the toxin into the spinal groove. Two possible methods of venom injection using this principle are described below:

The spine could be 'pre-charged' - That is the glandular cells could secrete venom into the groove and by capillary action the venom would travel up the groove and remain in the groove until the spine was used, Once the spinal groove was full the cells would stop secreting toxin and therefore preventing waste. The spine would act rather like a hypodermic syringe which would be used to inject the venom into the predator.

A slight modification of method 1 would involve the cells continually secreting the toxin into the groove resulting in some toxin loss.

No sensory cells were seen around the tip of the spine indicating that the mechanism employed by these fish for toxin injection isn't of the muscular type, injection of venom my muscles pressing onto the glandular mass, as this would require some form of trigger.

All these methods of venom injection are based on what was found require further investigation to prove or disprove these theories.

The opercular spine is made up from numerous layers. This laminated structure could have many advantages over a similar sized solid spine. This structure gives the spine added strength and durability, due to the presence of individual layers which enable the spine to bend slightly under pressure and any damage would be layer by layer.

If the spine was solid the entire spine could snap under similar pressure and the Weeverfish would be defenceless until the entire spine was replaced which undoubtedly would take longer than replacing a few cracked layers. This structure could also be related to growth, laying down different layers each year, and may be interpreted as growth rings.

The spinal layers could be laid down by the outer membrane covering the entire structure as pockets were seen along the inner most edge of the membrane which could have a secretary function, this is speculative and requires further investigation.

The general structure of the spine is in the form of a large opercular plate connected to which is a spine that has a groove running from the Basel groove terminating a short distance from the tip.

This structure is the same as other scientists (Allmen:1840, Skeie:1962) found in previous studies, although they do not mention the laminated structure of the spine.

This basic structure was also seen in other members of the weever family by Parker (1888) again with no mention of the internal structure.

The number of holes seen in the opercular plate could be due to the preparation process (artificial) or could be part of the spines structure, maybe acting as nerve or nutrient channels which serve the spine in someway or feed into the base of the venom gland supplying nutrients to this structure as they are seen directly behind the basal groove.

This investigation hasn't added any new information to that already known about the Weeverfish but has reconfirmed many of the points raised by other scientists (Allman:1840,Skeie:1962) related to the structure of the opercular spine and associated venom glands.

To my knowledge none of the previous authors mentioned the internal structure of the spine, which I found to be layered from my investigations. This discovery was due to accidental damage during preparation which exposed the internal structure of the spine.

This project also contains two possible methods of venom delivery not mentioned by previous authors (Allman:1840,Skeie:1962) along with one detailed description of one particular method based on the principle mentioned by Skeie (1962) of the glandular cells bursting releasing the toxin into the spinal groove.

The ideas contained within this project are just speculations and due to time constraints on this project will remain so until further investigations into the venom delivery, spine formation prove or disprove these ideas.