]g ART. 4.— BASHFOED DEAN. 



terminates in a posteriorly curved process which is doubtless the 

 serial homologue of the dorsal terminal of the shoulder girdle. The 

 ventral blade of the girdle bends ventro-mesad and come to lie in an 

 almost horizontal planes. 



IV. Viscera. 



A. Gills. 



As in other chimaeroids an opercular fold arises from the posterior 

 margin of the first ceratohyal, is strengthened by a series of parallel 

 cartilaginous rods, and encloses completely the excurrent openings 

 of the gill. An interesting feature however in the present form is 

 that the outer margins of the supporting tissue of the remaining 

 gill bars fuse together ectad, both dorsally and ventrally, and 

 together form a series of grooves which pass outward and fade away 

 near the external opening of the opercular fold. In the opercular 

 gill the vascular lamellae extend outward from the gill bar halfway 

 to the free margin of the fold, following closely the parallel 

 cartilaginous rays which strengthen it. In the remaining gills the 

 median supporting septa extend no further outward than the tips of 

 the vascular lamellae, a condition, however, which does not, of course, 

 apply to the extension of the supporting septa at their dorsal and 

 ventral ends, as already noted. Four gill slits are present, the fifth 

 having been suppressed. There is no trace of a spiracle. The number 

 of lamellae in the gills averages fifty : they are slightly less numerous 

 in the opercular gill, and in the hindmost hemibranch about 

 forty-five are present. It is interesting to note that the gill lamellae 

 are continued around the dorsal margins of the gill slits, and that 

 traces of them can be found around the ventral margins. Gill rakers 

 are present, but they are small, fleshy and widely separate from 

 one another, to be interpreted therefore, as rudimentary organs. 



