472 DR. W. G. RIDEWOOD ON THE CRANIAL [DeC. 13, 



opercular, The palatine, ectopterygoid, and entopteiygoid bear 

 teeth. The ectopterygoid has an outwai-dly projecting ledge 

 which serves to support the eyeball, and which comes into close 

 relation with the upper edge of the middle of the three large 

 bones of the suborbital series. The ectopteiygoid is curved in the 

 middle of its length, but not sharply bent. 



Opercular Series (text-figs. 131 and 132, pp. 470, 471).— The 

 gill- cover is large, and the opercular and subopercular bones are of 

 corresponding proportions. The branchiostegal rays are thirteen 

 in number ; eight of these are set on the outer side of the lower 

 edge of the ceratohyal, and five on the epihyal. The shape is 

 approximately the same in all, but the hinder ones are larger than 

 those in front. Valenciennes (Hist. ISTat. Poiss. xx. 1847, p. 469) 

 and Gunther (Brit. Mus. Oat. Fish. vii. 1868, p. 466) put the 

 number of branchiostegal rays as fifteen. 



Hyohranchial Series. — The lower hypohyal is slightly larger 

 than the upper. The posterior one-third of the glossohyal 

 cartilage is ossified ; a narrow membrane-bone with a row of 

 teeth along the middle covers the whole. The first, second, and 

 third basibraiichials are covered by separate membrane-bones, 

 each bearing a narrow central row of teeth, but the investing 

 lamina of the second basibranchial extends forward over the 

 hinder part of the first basibranchial. The ui'ohyal is long and 

 slendei'. The foui'th epibranchial is about as much expanded as 

 in the Hei'ring. The first pharyngobranchial is cartilaginous, 

 and a spicular bone rises from the front end of the first epi- 

 branchial, and is attached by ligament to the pro-otic at the point 

 marked s in text-fig. 130B, p. 469. 



Engraulis encrasicholus. 



The chondocranium of a young Anchovy of 25 mm. length has 

 been described and figured by Pouch et (Journ. Anat. et Phys. 

 1878, p. 75, and figs. 49 and 50), but the account has no impoi'tant 

 bearing in the present connection. 



Cranium (text-fig. 133, p. 473). — The most remarkable fea,ture 

 about the general aspect of the cranium is the considerable vertical 

 extent of the orbital i-egion, a feature directly I'elated to the large 

 size of the eyes. The jaarietals are separated, and on the roof of 

 the cranium is a pair of fontanelles, each bounded by the frontal, 

 paiietal, and supraoccipital. On the upper surface of each frontal 

 bone are two cross bars or arches of bone, the anterior one strictly 

 transverse, the second oblique. 



A distinct opisthotic is not present ; the deep or opisthotic 

 limb of the post-temporal is attached to a process of the exoccipital 

 lying immediately over the foramen for the tenth nerve. The 

 posterior temporal groove is shallow, and the tempoi'al foramen, 

 near its anterior end, is large and bounded by the frontal and 

 paiietal, with sometimes also a small portion of the squamosal 

 below. Owing to the large size of the squamosal bulla that 



