422 GRACE A. WELLS 



the upper surface of the tip of the snout, behind which is a 

 series of minute foramina for the passage of twigs from this 

 nerve (o.s. VII) to innervate the lateral line organs in the inter- 

 orbital region. In the postorbital process these foramina are 

 somewhat larger than those more anterior. 



Just dorsal and lateral to the postero-lateral angle of the 

 cranium is the foramen of the ninth nerve (IX), already referred 

 to. Between this and the occipital condyle is the larger open- 

 ing for the passage of the main trunk of the tenth or vagus 

 nerve (A"). Just anterior and slightly lateral to this foramen 

 is a smaller opening for the passage of a branch (probably the 

 first branchial) of the same nerve (X). 



Posterior to the median notch in the anterior wall of the brain 

 case there is a small heart-shaped opening in the cranial roof. 

 This marks the location of the epiphysis (e./.). In one speci- 

 men dissected this was a paired, instead of a single medial 

 opening. 



The regions of muscle attachment on the dorsal side of the 

 cranium are restricted to the posterior portion. The trapezius 

 (T.) attaches just lateral to the glossopharyngeal (IX.) foramen, 

 above the bar of the fenestra postotica; while on the postero- 

 medial angle of the bar is inserted the fibrous fascia of one of 

 the dorsal longitudinal muscles (D.L). Other dorsal longitudinal 

 muscles, corresponding in general to the protractor dorsalis 

 (Pro.d.) of Greene and Greene's description of the musculature 

 of the king salmon, attach to the cranial roof between the crista 

 occipitalis and the posterior semicircular canal. Still others 

 have their origin in the triangular depression between the supe- 

 rior and posterior semicircular canals. These muscular attach- 

 ments are even more clearly seen on the basal surface (fig. 7). 



In general outline the ventral surface of the cranium (fig. 2) 

 is much like the dorsal and the same regions may be recog- 

 nized. In front is the rostrum (r) with its strong median carina 

 (r.c.) and lateral to this the rostral bar (r.b.) with the dorsal and 

 ventral rami of connective tissue referred to in the description 

 of the dorsal surface, only the ventral ramus showing clearly in 

 this view. At the base of the rostrum, at the level of the nasal 



