Art. XXXVI.—On some new Marine Planarians.
[Read before the Wellington Philosophical Society, 20th August, 1881.]
The animals comprising this group are exceedingly interesting. They are usually thin, soft, and delicate; their varied colours, beautiful leaf-like forms and graceful movements render them attractive alike to the naturalist and the novice. They are, however, somewhat small, and adhere so closely to the sea-weed and stones amongst which they live as to require not only a sharp but an experienced eye to detect them.
Most of the members of this section are furnished with a pair of tentacles. In some species these are mere folds or ear-like projections, in others they assume the form of true tentacles, situate either occipitally or dorsally.
The mouth is situate on the under surface, in the median line, but may be either sub-central, pre-central, or post-central.
The ova may often be mistaken for those of nudibranch molluscs, being usually deposited in flakes on sea-weed, etc.
It is to be regretted that no preparation has yet been devised for preserving these animals without destroying the colouring, which is their chief beauty.
The two species now described were obtained in the neighbourhood of Wellington, and kept alive for several weeks. The shores of Cook Strait and Wellington Harbour appear particularly suited to them, and will, when thoroughly examined, probably yield many new and beautiful forms.
Thysanozoon huttoni, sp. nov.
Body oblong very thin, margin extremely irregular and puckered.
Upper surface uniform dirty yellow, irregularly blotched with brown, and having a broad, chocolate-coloured border.
Under surface steel grey, bordered with black; a broad, somewhat irregular patch of brown extends along the central two-thirds of the median line.
Head with two long tentacles of chocolate colour, but tipped with yellow.
Length, 2 inches.
Eurylepta herberti, sp. nov.
Body moderate, veined dendritically, margin much crenated and puckered.
Upper surface pale cream colour, with a darker brown median stripe running the whole length; margin white, with an inner border of bright red, and another and narrower one of deep brown,
Under surface pale grey, with darker along the median line.
Tentacles short, pale cream colour tipped with red.
Eyes numerous at the base of the tentacles.
Length, 1½ inch
Named after Mr. W. H. Herbert, to whom I am indebted for specimens of this beautiful species.