DR. A. GUNTHER’S DESCRIPTION OF CERATODUS. 
581 
median transverse strip (Plate XXXVI. figs. 2 & 3, a) and a large irregularly shaped 
piece (Plate XXXVI. figs. 2 & 3, b) with the articular condyle for the pectoral limb 
(Plate XXXVI. figs. 2 & 3, c, and Plate XXXV. fig. 1, he). The latter cartilage 
forms the base of a large concave bone (coracoid of Owen, clavicle of most other authors) 
(Plate XXXVI. figs. 2 & 3, d, and Plate XXXV. fig. 1, co ) ; and the whole arch is sus- 
pended from the skull by means of a broad suprascapula (Plate XXXVI. fig. 2, e, and 
Plate XXXV. fig. 1, ss). We proceed now to a detailed description of these parts from 
the skull outwards. 
The suprascapida * is a thin, broad lamella of an obliquely ovate shape, entirely 
ossified ; it forms the posterior wall of the capacious gill-cavity, fitting into the hinder 
angle of the lateral cartilaginous region of the skull, to the edge of which two of its 
sides are fixed by a short continuous ligament. Its distal portion is connected with the 
coracoid by a broad ligament, which allows the ends of the two bones to slide over each 
other. 
The coracoid is a long, curved, rather thin bone, strengthened by several longitudinal 
ridges, and extending downwards nearly to the median line of the arch. A suture 
running right across its middle (Plate XXXV. fig. 1, and Plate XXXVI. fig. 2), nearly 
on a level with the pectoral condyle, divides it into two subequal portions f. 
The humeral cartilage (Plate XXXVI. figs. 2 & 3, h) has an oblong form, spreading out 
into a shorter upper lamella covering the hinder side of the lower half of the upper 
coracoid bone, and into a longer lower lamella covering a great part, and projecting 
beyond the margin, of the lower coracoid ; it does not quite extend to the median carti- 
lage. The humeral cartilage is swollen behind into a thick condyle for the pectoral 
joint. 
The median cartilage (Plate XXXVI. figs. 2 & 3, a) is a single band connecting the 
two coracoids, into the interior of which it extends for some distance. More of it is 
covered by bone on the posterior side of the scapular arch than on the anterior. 
The Pectoral Limb. 
The parts of the pectoral limb are entirely cartilaginous, without a trace of ossifica- 
tion. The cartilage is distinguished by cells of rather short ovate shape, a great number 
of which have a double nucleus, or are even perfectly divided into two (Plate XXXVI. 
fig. 8). 
The paddle (Plate XXX. fig. 2) is joined to the scapular arch by an elongate, flattish, 
* In Lepisodiren “ suprascapulare” of Peters. 
f I cannot attach much value to this division ; the upper piece is certainly not homologous with the scapula 
of Teleosteous fishes, which is far removed from the region of the pectoral condyle. The division is also pre- 
sent in Lepidosiren ; only the upper piece is much the smaller, and Mr. Parker, by naming it superclavicle, has 
regarded it as the homologue of the scapula. A division of this hone has also been observed in Polyodon folium, 
where the lower piece is the smaller (see Gegenbatjr, Schultergurtel, Taf. 6. fig. 3), 
