PEOSOEHOCHMUS CLAPAEEDII. 175 



Colour pale yellow, or, in some, pale orange, with two translucent spots behind the eyes, 

 marking the situation of the ganglia. Long confinement increases the number of the dull orange 

 grains on the dorsum. The young have numerous orange pigment-specks in their skins at 

 birth. 



Head wider than the succeeding portion of the body, though not distinctly defined poste- 

 riorly, broadly spathulate as well as somewhat truncate in front, and with a well-marked central 

 notch from which a pale streak proceeds some distance behind the ganglia. Just behind the 

 notch is a transverse furrow, furnished with very long cilia, which have a radiate appearance 

 under the microscope. Eyes situated considerably behind the tip of the snout, the anterior pair 

 being the larger, and while those of opposite sides are widely apart, those on the same side are 

 closely approximated. The anterior pair under pressure often present a crescentic margin in 

 front, and I have seen a clear globule in connection with them, which may represent a lens. In 

 profile the two halves of the snout in front form a pair of large and prominent lips, with the 

 mouth underneath and behind— in the shape of a well-marked elliptical or ovoid slit, while a third 

 lobe, less prominent, occurs on the dorsum. The trilobed condition of the snout is well seen in 

 small specimens placed between glasses separated by a chip. 



Cephalic furrows. — A very slight notch is observed opposite the first pair of eyes, which 

 indicates the opening of the cephalic pit, and an indistinct furrow runs from this point inwards. 



P. Claparedii is not so active and restless in its movements as some of its allies, but it is 

 the most hardy four-eyed example of the Enopla I have yet seen, even more so than T. dorsalis. 

 The specimens bore a journey from the Channel Islands to Scotland without the loss of one, or 

 rather with a considerable increase, since the adults gave birth to numerous young individuals. 

 It is interesting to see the comparatively large embryo moving in the interior of the adult, with- 

 out interfering with its comfort in any way. They are observed in the bodies of their parents 

 in July, and some remained there till October, having meantime considerably increased in 

 size. Under pressure the embryos sometimes escape per anum. Both young and old are fond 

 of leaving the water and remaining on the side of the vessel in the open air, and dozens of the 

 former are frequently found floating on the thin whitish film which gathers on the surface of the 

 sea-water after long keeping. They appear to be somewhat social animals in the free condition, 

 as groups of adults (from ten to fifteen in number) are occasionally found in fissures of the rocks 

 at St. Peter Port, Guernsey. 



If the indefatigable Col. Montagu had published his notes and figure of this species it now 

 would have borne his name. He describes it as " long, filiform, yellow, with the front rounded 

 and slightly bifid. Pour eyes placed quadrangular." Pive were found entwined together on the 

 coast of Devon. He thought it might be the Planaria Candida of Muller, but the arrangement of 

 the eyes and other points in his figure, together with the description, show its real nature. 

 CErsted remarks that the anterior pair of eyes in his Tetrastemma subpellucidum are widest 

 apart, but we are otherwise left in doubt as to the actual species he describes. The 

 Polia fumosa of M. de Quatrefages has certain close resemblances to this form, such as the 

 arrangement of the eyes and the truncated snout, and it is difficult to see to what species the 

 author refers if not to this. The colouring of the figure (op. cit., fig. ix, a, b) is much too dark, 

 and the outline not at all characteristic. The enlarged anterior end, however, in fig. x, though not 

 accurate, can scarcely apply to any other species. He found it in fissures of the rocks at St. Vaast 

 and Brehat. It was not till more than half a century after the English naturalist's observations 



