Gutty Marine Laboratori/j St. Andrews. 79 



backward behind the flipper, where the lower (or inner) one 

 rather rapidly widened and split into two, which became 

 broader, as usual, in their backward progress. The next 

 furrow was very narrow nnder the jaw, but gradually in- 

 creased into a broad ridge in its course along tlie region 

 behind the flipper. The succeeding narrow ridge split about 

 the middle of the sublingual region, the left ridge running 

 backward to a point considerably behind the flipper, where it 

 ceased, nearly in a line with the letters J. P. cut into the 

 skin, a single broad ridge (3 inches) passing backward 

 behind this point But the second or inner ridge formed by 

 the split was still more interesting, for it terminated by 

 fusing with the narrow ridge to its inner or right side about 

 a line midway between the eye and the anterior border of the 

 flipper (insertion ofj, the single ridge then coursing back- 

 ward to join the previous one in forming the broad abdominal 

 ridge (3 inches) formerly mentioned. The sublingual ridge 

 to the right split about a transverse line from the mandibular 

 condyle, the separating farrow ending a little in front of the 

 previous one and the letters J. P., a broad ridge not quite 

 3 inches remaining to the rear. Two subgular ridges to the 

 right, fused at a line a little in front of the flipper, contracted 

 to a narrower single ridge, the furrow ceasing under the 

 letters J. P., leaving posteriorly a broad smooth area more 

 than double the breadth of the Avidest ridge previously 

 described. The adjoining furrow to the right presented a 

 rudimentary split at its inner edge in a line with the flipper, 

 but it soon ceased, and the furrow to the right terminated a 

 little short of the previous one. The next ridge (to the 

 right) Wi.s split about the middle of the sublingual region, 

 its lower liml) forking again in a line with the eye, whereas 

 the next one (also to the right) fused with its neighbour to 

 form a single ridge at the same line. The ridges slightly 

 widen from the articulation of the mandible forward to its 

 edge, the narrowest part being the region of the throat, and 

 some helow the eye are short, ending after a brief course on 

 the side or fusing into a single ridge. Moreover, whilst the 

 ridges, as a rule, are pale, the furrows have much dark 

 pigment. This description leaves about half the series 

 (to the right) untouched, but it will suffice to indicate that, 

 M'hilst there is truly a parallelism in the ridges, the condition 

 is more complex, as the accompanying photograph will 

 show. Mr. Beddard and others are inclined to think that 

 these ridges are useful to the animal in distention of the 

 mouth and gullet in taking food (fishes &c.), but, as they also 



