223 



distinct four-sided lozenge-sliaped cartilage let in to the arch, as it 

 were, in front", and "regards it as temptingly like a presternal". 

 Parker again in his paper writes: "Two Curved areas of fibrous 

 tissue with their convexities towards the median plane, extend from 

 the anterior to the posterior border, touching one another in the 

 centre and thus bounding two distinct cartilaginous areas — an 

 anterior (pre-omosternum) of a rhomboid and a posterior (post-omo- 

 sternum) of a triangular form" (Fig. 2). 



HuBRECHT 1) states that the two sides of the shoulder girdle in 



Fig. 2, 



Ft. Ost 



Fig. 1. Median ventral region of the shoulder-girdle of Hexanchus griseus. 

 Seen from above. Natural size. 



Fig. 2. Median ventral region of the shoulder-girdle of Notidanus indicus. Ven- 

 tral aspect. Natural size. Copied by kind permission from Nature. 



Cor. Coracoid region; Pr. Ost. Pre-omosternum; Ft. Ost. Postomosternum. 



1) HuBEECHT, Bbonn's Tierreich, Fische, 1876, p. 77. 



