Unnamed Vissians
The following is a list of unnamed Vissians.

Chief engineer 

The Vissian chief engineer was married to Calla. The two ultimately decided they would have a baby, and after a long wait, they were finally given a cogenitor with which to breed. 

In 2153, the Vissian chief engineer was among the members of the delegation who were welcomed aboard  as a part of a cultural exchange. During the exchange, he gave Commander Tucker, the chief engineer of Enterprise, a tour of the Vissians' engine room, but Tucker was particularly curious about the engineer's cogenitor.

When Tucker lied about his position aboard the Vissian ship in order to teach their cogenitor how to read and think for itself, the Vissian engineer refused to allow Tucker back aboard the Vissian ship. The issue was further complicated when the cogenitor requested  aboard Enterprise. The Vissian engineer and his wife demanded that the cogenitor be returned, believing that the Enterprise crew did not respect their culture. Their demands were ultimately met, but the cogenitor committed suicide soon after the Vissians left Enterprise, eliminating the Vissian couples' chances of having a child in the near future. ()

Cogenitor

Crewmembers  
These Vissians were members of Captain Drennik's crew that was studying a hypergiant star when his ship made contact with Enterprise. The first five visited the mess hall aboard Enterprise as part of the delegation. The sixth crewmember was working in the engine room aboard Drennik's starship when the chief engineer gave Trip Tucker a tour. ()  

Vissians