AMPHIPORUS BIOCULATUS. 163 



Head with a snout narrower than the succeeding portion; bluntly pointed, and similar in 

 shape to the head of a short spear or harpoon. In the median line is a grooved ridge, which, 

 although cut by the cephalic furrow, is continued some distance along the dorsum of the body. 

 On each side of the ridge is a longitudinal hollow on the snout. The eye- 

 specks are placed a little behind the tip of the latter, and from their deep ~piG. 9. 

 situation are somewhat indistinct. When viewed laterally the peculiar tapering 

 of the snout resembles the hoof of a horse. The mouth is marked on the under 

 surface, either as a slit like a key-hole, or as a linear depression (fig. 9) — ren- 

 dered conspicuous by its pigment, according to the degree of contraction : in 

 few species, indeed, is it so well seen. 



Cephalic furrows. — At the posterior border of the snout a well-marked 

 groove proceeds inwards and slightly forward on each side to the median 

 ridge, where a A-shaped process is formed by a sudden turn of the 

 furrow inward and forward. The groove is continued on the ventral surface 

 in a similar manner, and also has a slightly developed median angle at the 

 mouth. 



Under surface of the 



This curious form combines the hardihood of A. lactifloreus with the irrita- anterior region of 

 bilityof A. pulcher. It is exceedingly contractile, becoming quite baccate AmpHporusMsta- 

 when stimulated ; the head being withdrawn through a collar of the body, as krged. 

 in the latter species. The grooves of the snout during the various movements 

 become much exaggerated, and give the animal a very characteristic appearance. In minute 

 anatomy it belongs strictly to the Amphiporidce, the large proboscis, moreover, being furnished 

 with four marginal stylet- sacs. 



Amphiporus bioculatus, n. s. Plate VIII, fig. 3. 



Specific character. — Dull orange ; snout acutely pointed, with a distinct cephalic furrow 

 forming an angle directed forward at its posterior boundary. Eyes two, placed at the extreme 

 tip of the snout. 



Habitat, — Amongst tangle-roots attached to horse-mussels, in eight fathoms, Bressay 

 Sound, Shetland. 



Body about an inch in length, and rather more than a line in breadth, rounded, increasing 

 in diameter from the pointed snout almost to the posterior third. The tail is rather blunt. 



Colour dull orange, or pale brownish, inclining to reddish in front, especially in the region of 

 the snout. Under surface somewhat pale. 



Head with a small, pointed snout, which is bounded posteriorly by an angular furrow 

 (woodcut, fig. 10). The mouth is indicated on the ventral surface by a streak running forward 

 from the arch of the latter (woodcut, fig. 11). Two eyes, consisting of simple masses of black 

 pigment, are observed at the tip of the upturned snout (woodcut, fig. 10). 



Cephalic furrows. — Viewed from the dorsum the furrow passes from each side of the snout 

 inwards and forward, so as to form an angle. On the ventral surface, again, it makes an arch 

 with the convexity directed forward, the slit for the mouth springing from the centre. The 



