1904.] 



OSTEOLOGY OF CLUPEOID FISHES. 



471 



a still shorter lamellar limb overlapped by the back of the supra- 

 tempoi"al. The supratemporal forms a kind of outer wall to the 

 large pre-epiotic vacuity. There is also a pair of ordinary body- 

 scales, about as large as the supratemporals, which project back 

 from the transverse ridge of the parietals. These, together with 

 the supratemporals and the preoperculai-s, form a kind of girdle 

 around the top and sides of the hinder part of the head. The 

 preopercular is triangular in shape, with a concave anterior 

 border ; the horizontal limb is more than half as long as the 

 upright limb, and makes with it an angle of about 100 degrees. 



Gircumorhitcd Series (text-fig. 131, p. 470). — This series consists 

 of seven bones : a small nasal, a long narrow bone overlying the 

 prefrontal, and five others of moderately large size. 



Maxillary Series (text-fig. 131, p. 470). — The premaxilla is un- 

 usually short, and has the form of a flat, square scale, overlapping 

 the anterior portion of the maxilla, and with teeth along its lower 

 edge. The maxilla is fairly long and is toothed along the whole 

 length of its lower edge. There are two surmaxillee. 



Mandibular Series (text-figs. 131 and 132). — The mandible 

 closely resembles that of the Herring, and the highest point lies 

 over the anterior half of the ramus. Long, curved, pointed 

 teeth, similar to those of the maxilla and premaxilla, occur along 

 the antero-superior edge of the dentary. The angular bone is 

 separate ; there is no distinct sesamoid articular. 



ope 



Text-fig. 132. 

 hw. 



Dussimiieria acuta, hyopalatine avcli, opercular bones, and mandible of left side, 

 mesial aspect. For explanation of lettering see p. 493. 



Hyopalatine Series (text -fig. 132). — The hyomandibular has two 

 distinct heads for articulation with the cranium, the posterior 

 slightly largei- than the anterioi-. The symplectic makes an angle 

 of about 1 25 degrees with the axis of the hyomandibular ; it is 

 flat, and is largely overlapped on its inner sui'face by the inter- 



