768 MR FRANK J. COLE 
longitudinal rods, of which the two lateral are larger and more irregular in shape than 
the rest, and are called by AyERs and Jackson the lateral plates (fig. 6, J. p.). The seven 
dorsal ones are all very narrow and straight, the middle one occupying the mid-dorsal line. 
The spaces between these rods are of regular shape except the two lateral, and they are 
perceptibly wider than the rods themselves. There are seven olfactory lamime in 
Myzxine, produced by a corresponding number of longitudinal invaginations from the roof 
of the olfactory chamber. The lateral plates lie at the side of the bases of the 
most lateral laminze, whilst the other seven bars are situated immediately above the 
dorsal bases of the laminz. Thus the form of the capsule is clearly identified with 
the conformation of the olfactory organ, and is essentially the same both in Myaxine and 
Bdellostoma. | 
Whilst examining a series of transverse sections I discovered a cartilaginous connection 
between the posterior transverse bar of the olfactory capsule and the hypophysial plate, 
which I afterwards found by careful dissection of the adult animal (figs. 1 and 2, h. p.’). 
It was not seen by J. MULier, Parker, or Ayers and Jackson, but I| learned afterwards 
that it was described for Myaine by Neumayer,* and it has lately been independently 
mentioned by ALLIs in Bdellostoma.t It consists of a small cylindrical rod passing from 
the ventral extremity of the posterior transverse bar downwards and backwards to fuse 
with the hypophysial plate just where the latter fuses with the trabecula. There is 
thus at this point a complete ring round the nasal organ and the hypophysial tube— 
formed above by the olfactory capsule, at the sides by the connections now in question, 
and below by the hypophysial plate. 
The nasal rings consist of the white soft cartilage, but the olfactory capsule, with 
the exception of the anterior transverse bar, is formed of the brown hard cartilage. The 
anterior bar seems to represent a transition condition, whilst the larger lateral bars of 
the capsule are the toughest of all. 
NEUMAYER’S results on the nasal tube and capsule are sufficiently remarkable to call 
for special notice. The material he used was that collected by O. Maas for his well- 
known work on the renal organ of Myxine, but he does not state the size of the 
specimen on which his wax model was based. It was, however, probably Maas’ 8°5 or 
9°8 cm. Hag. The nasal tube is described and figured as a continuous cylinder with a 
few irregular perforations, and no indications of its tracheal nature, except perhaps as 
regards the first three rings. If this description is confirmed, then we must regard the 
nasal tube of Myaine as primitively a more or less continuous structure which has 
secondarily become differentiated into rings. Similarly, the anterior transverse bar of 
the capsule would seem to belong rather to the tube, as indeed is otherwise probable, 
since two of the nine longitudinal rods fail to reach it. NeruMaAYER also figures, but 
does not describe, a fusion of the anterior transverse bar of the capsule with the palatine 
bar and of the postero-ventral region of the tube with the subnasal cartilage (“ inter- 
* Op. cit., p. 3 and fig, 4. Apparently also by PotLaRD (p. 396). 
+ Anat. Anz, Xxiii., pp. 269-270, 
