TINS OF GANOIDS AND TELEOSTS. 547 



In a second specimen exaraiued, twenty-two fin-rays were 

 present, the first three in this case being supported by the 

 proximal segments of the first two radial elements. 



Anal Jin. — This fin very closely resembles the dorsal fin. 

 There are fewer radial elements and fin-rays, viz., eighteen and 

 twenty respectively, but all the central fin-supports are tri- 

 segmental. 



Cypeinid^. 



Sarhus vulgaris. 



Dorsal fin. — In this Cypriaoid the dorsal fin consists of twelve 

 fin-rays, supported by ten radial elements (PI. XXI. fig. 12). Of 

 the latter the fifth to the ninth (r.e.^-r.e.^) inclusive are the most 

 complete, each consisting of proximal (p.s.), mesial (m.s.), aud 

 distal (d.s.) segments. Each proximal segment is a relatively large 

 and somewhat dagger-shaped bone, which for a variable portion 

 of its length articulates by its sti'aight aud almost parallel 

 anterior and posterior margins with the corresponding edges of 

 the proximal segments iu front and behind, and is traversed on 

 each of its lateral surfaces by a prominent longitudinal ridge. 

 The distal end of the segment is greatly thickened, and provided 

 anteriorly with three facets, one median and two lateral, and 

 posteriorly with a fourth articular surface. The mesial segments 

 are short thick ossicles, suturally united at one extremity to the 

 posterior facet on the distal end of the corresponding proximal 

 segment, and with the usual oblique inclination backwards to its 

 articulation with the somewhat quadrate aud much smaller distal 

 segment. The distal segment, as well as the contiguous maro^in 

 of the mesial segment, rest inferiorly on the median facet of the 

 next succeeding proximal segment. The first to the fourth 

 radial elements (r.e.^-r.e.^) inclusive lack separable mesial seg- 

 ments, but possess instead, at first a facet, and ultimately an 

 upwardly and backwardly directed postero-superior process with 

 a terminal articular surface for the distal segment. The tenth 

 or last (v.e.) is a vestigial element, being represented by a 

 proximal segment only. 



Of the twelve fin-rays, the first four are spines of variable 

 length, decreasing in size from behind forwards ; the remainder 

 are soft multiarticulate rays. The first three spines are carried 

 by the laterally expanded distal end of the proximal segment 

 of the first radial element. The fourth, or large defensive spine 



4i* 



