28 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
little of it, and the anterior part of the ethmoid, as seen by the final 
position of the anterior ends of the pterygo-palatines, having turned 
not more than 45 degrees. 
In the turbot, according to Traquair (65, p. 276), the nasal region is 
nearly normal in position, the sagittal plane of the anterior part of the 
head nearly coinciding with that of the body. 
f. Comparison of Bothus with Pseudopleuronectes americanus. 
The nearest representative in American waters of the sinistral turbot 
is Bothus, the sand-dab, and I shall now compare briefly its turning 
with that of P. americanus. The sand-dab is much deeper than the 
flounder, but being thinner, though of the same length, it weighs about 
the same as that fish. Its translucency has gained for it the name of 
window-pane. 
Traquair’s statement that the turbot is less unsymmetrical than the 
plaice holds as truly here, the sand-dab being less distorted than the 
winter flounder. The mouth is straight and the length of the Jaw on 
the ocular and eyeless sides is more nearly equal. The mouth is much 
larger and the gape greater than that of the winter flounder. The nasal 
pits are very nearly symmetrical, that of the right side being, however, 
a little the higher (Plate 3, Fig. 13). The transposed eye is not at all 
posterior to its mate, as is the case in P. americanus. The dorsal fin in 
this species reaches forward entirely past the right eye (Plate 3, Figs. 13, 
16, crt. pin. d.). After the passage of the eye, the bases of the fin rays 
arise nearly over the right wing of the ethmoid. 
The ethmoid is relatively a much more slender cartilage in Bothus 
than in P. americanus. The cross section of its anterior end (Plate 8, 
Fig. 13) has the shape of an inverted letter T, and its dorsal margin is 
turned not more than 20 degrees to the left from the sagittal plane. In 
the posterior region (Fig. 16) the ethmoid is turned about 45 degrees. 
The relation of the cartilage marked trd. sw’orb. s. to the ethmoid mass 
in Figure 16 indicates the angle, though the median bar itself is farther 
forward. The wings of the ethmoid fuse to the median bar in a peculiar 
way. The right wing (ec’eth. dx. Fig. 13) points toward the rays of the 
dorsal fin which lie next it. It does not connect with the basal part of 
the ethmoid directly, but merely with the median upright part. The 
left wing has a process running anteriorly into the region of the lip 
at the level of the basal part of the ethmoid, with which this wing is 
fused. It then passes around the olfactory nerve of its own side, be- 
