460 J. FRANK DANIEL 
joint to be attached to the lower ventral margin of the mandible. 
Further, it may be said that a slip from this ligament, the liga- 
mentum hyomandibulo-mandibulare (l.hm-m.), passes upward 
to be attached on the hyomandibula, just proximal to the 
quadrate slip of the median ligament and directly under the 
attachment of the hyomandibulo-quadratum. It thus results 
that a puncture through the fibers of the superior post-spiracular 
ligament and through the attaching fibers of the ligamentum 
hyomandibulo-quadratum would perforate the attaching fibers 
of this ligament. 
Finally other ligaments may here be mentioned. Strong 
fibrous bands run lengthwise of the lateral or concave surface 
of the mandible and the palato-quadrate to the quadrato- 
mandibular joint. The one on the mandible sends a slip upward 
to attach on the quadrate just mediad of the first (anterior) 
articulation. A similar slip from the quadrate attaches on the 
mandible just mediad of the second (posterior) articulation. 
These two attaching ligaments form a curious type of scissor 
ligament. 
The cartilaginous gill-rays. There are present on the hyo- 
mandibula (epihyal) and on the ceratohyal segments of the 
second arch, cartilaginous rays which project outward and 
backward as supports for the gill septa. These show con- 
siderable variation in different specimens. In one of the large 
males the first six of these on the hyomandibula fuse at their 
proximal ends into two masses. The sixth is followed by nine 
single rays which meet and fuse at their proximal ends into a 
half arch. Eight single rays of the ceratohyoid, similarly fusing 
at their base, complete the arch. This arch then encircles the 
articulation between the two segments. Following these upper 
ceratohyal rays there are six pairs of rays fused at the bases into 
three pieces, and following these there are two or three stout rays. 
The first branchial arch (fig. 10) consists of four segments, 
three of which are shown in figure 10. These, counted from the 
dorsal to the ventral side, are: (1) the pharyngobranchial 
(p-b.), (2) the epibranchial (e-b.), (3) the ceratobranchial (c-b.), 
and (4) the hypobranchial (h-b., see fig. 11). From below, the 
