1904.] 



OSTEOLOGY OF CLUPEOID FISHES. 



457 



over the hinder half of the ramus ; in Clupea harengus and Clupea 

 sprattus it lies over the front half. The mandibular symphysis is 

 more in advance of the premaxillfe in the two latter species than 

 in the first. The angular bone is distinct. There is a small 

 sesamoid articular in Clupea finta, but not in Cl'ap>ea harengus. 

 There are about five teeth situated in a row at the anterior end 

 of the dentary in both species. 



Hyopalatine Series (text-fig. 124). — As lias been pointed out 

 by Matthews {I. c. p. 289), the hyomandibular of Clv/pea finta 

 articulates with the cranium by two distinct heads, whereas in 

 Clapjea harengus the hyomandibular has a single broad head. 

 On comparing Clupea jintoj and Clupeoj harengus, the quadrate 

 is seen to be more forwardly rotated in the latter, and the 

 hyomandibular to slope more forward. The angle in the middle 



Text-fig. 124. 



ope. 



Sep- 



pop 



wp sy 



Clupea finta, hj'opalatine arch, opercular bones, and mandible, left side, mesial 

 aspect. For explanation of lettering see p. 49-3. 



of the ectopterygoid, also, is smaller, so that the forward displace- 

 ment of the quadrate-articular joint does not afiect the front part 

 of the hyopalatine arch. It results, however, in the forward 

 extension of the mandibular symphysLs in front of the pre- 

 maxillaries, and is accompanied by an elongation of the inter- 

 opercular and the lower limb of the j^reopercvdar. 



The symplectic is rather small in Clupea finta ; it is relatively 

 longer and more slender in Clupea harengus. The lower end of 

 the symplectic of Clupea fintOj is abruptly terminated, and is 

 not enveloped by the quadrate as is so generally the case. The 

 palatine is shorter and broader in Clupea finta than in Clupea 

 harengus, and has a distinct cartilaginous head for ar-ticulation 

 with the prefrontal, whereas in Clupea harengus it is the pre- 



