The Osteology of Dallia pectoralis. 257 
The ligament joins the cranium near the middle of the posterior 
surface of the exoccipital, the opisthotic being absent as stated 
elsewhere in this paper. In none of several specimens examined 
is the ligament ossified entirely to the cranium. Thus the post- 
temporal is entirely free. In the majority of fishes there is a short 
ligament from the lower fork connecting it with the cranium. 
The shoulder girdle is laterally braced by the stout nearly 
straight first rib, which is interposed and securely attached between 
the lower end of the supraclavicle and the head of the clavicle. 
The supraclavicle is long, slender, and expanded towards its 
lower end: It is rather narrowly attached to the posttemporal. 
The clavicle is a long slender curved bone, not much expanded 
anywhere, and has a simple rounded thin head. It is somewhat 
folded over or hollowed on its posterior surface for the reception 
of the other elements of the shoulder girdle. No postelavicle is 
present. 
The other elements consist of: 1) A triangular basal cartilage, 
one side of which is attached to the clavicle, and with the outer 
lower angle prolonged into a thickened styliform rod. A round 
foramen is present near its upper end. 2) Attached to the outer 
edge of this basal element is a thin delicate plate of cartilage, nearly 
round in outline, and more or less completely divided into an upper 
and lower half. In about half of the numerous specimens examined 
the incision between the halves does not completely divide them 
(as shown in the accompanying figure B). In the others they are 
entirely divided. Toward the distal edge the plate begins to divide 
rather irregularly into narrow strips which nearly but not quite 
coineide in number with the pectoral rays. The incisions between 
the strips are of varying lengths, and near the middle of the plate 
are a few short slits which do not communicate with the marginal 
incisions. 
The pelvic elements are very small rather simple rods, which 
converge inward from the base of the fins to meet on the 
median line. 
Vertebrae, ribs, and vertical fins. 
The vertebrae number: abdominal 21, caudal 18, which with 
the hypural element is a total of 40. 
All of the abdominal vertebrae have developed parapophyses 
