484 



EDWIN S. GOODRICH. 



theui.^ 'LMie actinotricliia are more numerous tliau the jointed 

 rays which develop outside them, and become grouped 

 together at the edge of the fins below the growing definitive 

 rays (Text-figs. 2 — 4), 



3. The definitive bony tin-rays, or lepidotrichia : 

 typically ossitied, jointed, and branched. These dermal rays 



Fig. 1. — Diagrammatic figure of a section through the dorsal tin of 

 Scy Ilium. For the lettering sec p. 517. 



are found in all Teleostomes, in both the paired and unpaired 

 fins (excepting the ''adipose " fin). 'Jlie hard ossified seg- 

 ments are joined together by narrow, fibrous, uncalcified 

 regions, forming flexible articulations, comparable to the 

 ligaments uniting ganoid scales to each other. In specialised 

 forms the lepidotrichia may undergo various modifications, 



' Should this conclusion be borne out, the name actinotricliia might 

 perhaps be dropped in favour of tlie more descriptive term ceratotriciiia. 



