478 
ME. W. K. PARKER ON THE DEVELOPMENT 
(i.op.), behind. The circumorbital series is a very perfect ring of small scutes round the 
eye-socket; of these the antero-superior scales are the largest. A short chain of three 
or four small scutes runs forwards from the super orbital part of the ring ; these may 
be called preorbitals (p.ob.) ; they are tilted up and form a sort of u eave” to the 
large convex coronoid part of the mandible. There, indeed, in front of the eye-balls, 
the skull is pinched inwards, and set, as in a vice, between the high hinder part of the 
lower jaw, whose steep, almost vertical, hind margin chafes, so to speak, right and 
left, against each circumorbital ring (Plate 37, fig. 1). 
Below the tilted preorbitals there is another short, feeble chain of three or four 
scutes ; the last but one of these lyn.x".) is as long as the others together, and has all 
the relations of the free part of the edentulous “ os mystacum,” or maxillary of 
typical Teleosteans ; the little scute behind it (/.) shows the same relations as the 
small malar (jugal) of many Teleostei. 
Outside of and protecting the sub-marginal row of mucous glands, there is a long 
chain of bones (see Plate 32, fig. 5, m.c.g., and Plate 37, figs. 1, 2, m.x'.) ; this series 
of scutes is the continuation of the mystaceum series (.) but thrice their width; 
this may be called the maxillar y chain. This is composed of about fourteen or fifteen 
very similar scutes ; they are oblong, their width being about half their length. In 
front of these the small premaxillaries ( px.) are seen to be distinct, right and left. 
Each moiety (or centre) is pointed in front, has a small palatine plate and a dentary 
edge with sharp teeth ; these rows of teeth (fig. 3, px.) meet in front at an acute 
angle. * 
Behind the palatine plate of the premaxillaries, right and left, there is a long bone 
in close contact with its fellow of the opposite side, and so slender that the two- 
together are not so wide as a single ethmo-nasal (fig. 2, et.n.) ; these “needles” are 
the vomers (fig. 3, v.) ; they become covered with a very fine rasp of teeth, and are 
nearly half the length of the entire skull. 
Bounding these, along the palatal face of the rostrum, there is a pair of bones one 
seventh longer than the vomers, and twice as wide ; these are the “ parosteal palatines ” 
(pa'.). These bones become invested with a rasp of teeth a degree coarser than that 
on the vomers. 
In the long valley between these palatine splints and the maxillary chain there 
is a row of laxge sharp teeth, and on the edge of the chain an outermost row of 
small sharp teeth. A very long carinate, trough-like bone runs over the hind part of 
the two vomers for a Considerable distance, and then extends to the end of the skull; 
on escaping from them it appears also rough, with a fine rasp of teeth. Further 
back these teeth cease, but the bone is carinate up to the basi-pterygoid (bpg.) ; this 
is the parasphenoid (Plate 37, fig. 3 , pa.s.) This bone is wider in the ethmoidal than 
* In an old specimen I find a flat sub-arcuate sente binding across in front of the distant pre¬ 
maxillaries ; this latter bone might be thought to be an edentulous azygous premaxillary and the two 
next behind it, not premaxillaries, but the foremost of the maxillary chain; 1 incline to call it a prenasal. 
