
Tetrastemmatid nemertean
      Tetrastemma melanocephalum
- exerted proboscis 1
Tetrastemmatid nemertean
      Tetrastemma melanocephalum
- anterior dorsal view 1
Tetrastemmatid nemertean
      Tetrastemma melanocephalum
- on rock underwater 1 
Tetrastemmatid nemertean
    Tetrastemma melanocephalum
    - on rock underwater 2
Tetrastemmatid nemertean
    Tetrastemma melanocephalum
    - on rock underwater 3
Tetrastemmatid nemertean
    Tetrastemma melanocephalum
    - coiled / dorsal view 1
  
Tetrastemmatid nemertean
    Tetrastemma melanocephalum
    - coiled / dorsal view 2
Tetrastemmatid nemertean
    Tetrastemma melanocephalum
    - anterior dorsal view 2
Tetrastemmatid nemertean
    Tetrastemma melanocephalum
    - markings and eyes 1
Tetrastemmatid nemertean
      Tetrastemma melanocephalum
- markings and eyes 2
Tetrastemmatid nemertean
    Tetrastemma melanocephalum
    - stylet 1
Tetrastemmatid nemertean
    Tetrastemma melanocephalum
    - stylet 2
Tetrastemmatid nemertean
    Tetrastemma melanocephalum
    - proboscis 1
Specimen above found in a sample of Coral Weed, Corallina officinalis, taken from the lowershore at Chimney Rocks, Penzance, Cornwall. 03.06.15.
Tetrastemmatid nemertean
    Tetrastemma melanocephalum
    - dorsal view 1
  
Tetrastemmatid nemertean
      Tetrastemma melanocephalum
- dorsal view 2
Tetrastemmatid nemertean
      Tetrastemma melanocephalum
- dorsal view 3 
Tetrastemmatid nemertean
      Tetrastemma melanocephalum
- anterior 1
Tetrastemmatid nemertean
      Tetrastemma melanocephalum
- anterior 2
Species above found in a sample of coralline algae taken from the lowershore between Gyllynvase and Swanpool, Falmouth, Cornwall. 06.12.14.
Professor Juan Junoy states that this species is what he would consider Tetrastemma melanocephalum, but it is not possible to confirm the identity as there are other similar looking species. It must be noted that the images here are of only one specimen, which has dorsal rather than lateral speckling, which is described by Ray Gibson.
I have been informed, 09.12.14, by Professor Juan Junoy of the EU-US Marine Biodiversity Research Group, Universidad de Alcalá, Spain; that black-headed species of Tetrastemma are currently under revision using DNA analysis. It is likely there will be more black-headed Tetrastemma species described as a result of DNA analysis, than have been described in previous works on nemerteans e.g. those by Ray Gibson.