1875
Both these forms are near H. Theobaldi but may be distinguished at once by the absence of the white stripe on the edge of the left lobe of the mantle and by the longer form of the shell. [...] with a darker shade of the same the mantle covers nearly the whole shell ; a narrow white line coihmeneing near the posterior margin of the slit disclosing the shell etends round towards the respiratory orifice on the right hand side and in0 II. [...] 4. Animal of a fine orange pink grey on under side of the foot; tentcles short mantle ()Wiggly covering the shell with only a slight trace of a longitudinal opening running back from the anterior left side three paralel bands of greenish grey along the back of the neck the eye-tentacles being of the saileiolour. [...] of their tip (the curved upper walls of the nasal cartilages being also copletely ossified and ankylosed to the inner surface of the nasals and maxillaries for the same distance) ; here there is a break and the bone is perfectly smooth for a space of 2 inches when there commences a diamond shaped roughened surface which occupies the whole of the remaining at in. [...] in advance of the anterior point of the prsemaxillse between which point and the lower edge of the septal bone there is a distance of one inch.