THE SESAMOID ARTICULAR 23 



THE SCYPHOPHORI. 

 Gymnarchus niloticus. 



Dr. Ridewood presents a good plate of the mandible of this form 

 (Linn. Soc. Jour., XXIX, pi. 23) in which the sesamoid articular is 

 shown to be nearly as large as the endosteal articular, with which it is 

 connected by a deeply dentate suture. It lies against the ectosteal part 

 of the articular. 



In the above paper a sesamoid articular is reported to be present in 

 Mormyrops deliciosus, but not present in Pterocephalus bane. 



THE HAPLOMI AND XENOMI. 

 Umbra lima, Dallia pectoralis. 



These two are similar in having the sesamoid articular very large, 

 attached far forward on the ectosteal plate with which it is broadly con- 

 nected, concave on its lower surface to fit over Meckel's cartilage, and 

 far remote from the endosteal part of the articular, which is little larger 

 than is necessary to form the condyle for the quadrate. 



Esox reticulatus. 



The sesamoid articular is much smaller than in Umbra, and not 

 placed so far forward on the ectosteal plate of the articular, nor so 

 broadly connected. Otherwise it and the condition of the small endo- 

 steal part of the articular are similar. 



Fundulus similis. 



The large sesamoid articular lies about equally over the top of the 

 endosteal process and Meckel's cartilage, with its outer surface against 

 the ectosteal plate. The endosteal part of the articular, unlike that of 

 Esox, is ossified well forward. 



THE SYNENTOGNATHI 

 Tylosurus marinus, T. acus. 



The sesamoid articular is an exceedingly large, flat bone, suturally 

 attached to the ectosteal plate of the articular, and at its lower edge to 



