FINS OF GAKOIDS AKD TELEOSTS. 593 



excluding tlie BlenniidiB, the supporting elements o£ the hinder 

 soft-rayed portion o£ the dorsal fin and also those of the anal fin 

 (if present) are bisegmental ; and the same may be said of the 

 fin-supports of the spinose portion of the dorsal fin in the 

 Percidai, Sparidse, Scombridse, and Carangidae, and of the whole 

 dorsal fin of the Trachypteridse. On the other hand, in the 

 Cottidse, Mugilidae, Labridae, and Eistulariidse the anterior 

 spinose dorsal fin is supported by radial elements which consist 

 only of proximal segments, and are therefore unisegmental. In 

 the BlenniidsB the whole of the extensive dorsal fin is supported 

 by unisegmental eleinents. As a rule, the posterior soft-rayed 

 part of the dors^al fin and the anal fin more or less closely agree 

 in the character of their radial elements ; the Blenniidse, in which 

 the elements of the dorsal fin are unisegmental while those of the 

 anal are bisegmental, being the only family in which there is any 

 marked difference between the two series. 



Indications of the suppression of segments are not wanting in 

 fins in which the majority of the radial elements are either 

 trisegmental or bisegmental : this is apparent, for example, in 

 Ferca, where the last three elements of the spinose part of the 

 dorsal fin have lost their distal segments, and in Aulostoma, 

 where the last two of the posterior dorsal fin are similarly 

 modified. 



In nearly all the Acanthopterygii the proximal radial segments 

 of the dorsal and anal fins are furnished with postero-superior or 

 postero-inferior processes with the usual articular relations : they 

 are, however, usually wanting in the more anterior elements of 

 each fin. 



In the more typical Acanthopterygii, such as the Berycidse, 

 Percidse (excluding Jiesopr«o?z) , Sparidse, and the Scombridae, the 

 postero-superior processes in the spinose part of the dorsal fin, 

 and the distal radial segments which articulate with them, are 

 laterally expanded and bent upwards so as to form sections of a 

 continuous, medio-dorsal, bony groove for the reception of the 

 spines when deflected. In the Cottidae, where distal segments 

 are wanting, the postero-superior processes are alone concerned 

 in the formation of the groove. In others, as in the Blenoiidae, 

 the groove is absent. Occasionally, through their considerable 

 increase in length, the postero-superior and postero-inferior pro- 

 cesses serve to connect together the otherwise widely separated 

 radial elements which support externally distinct fins or finlets, 



LINN. JOUEN. — ZOOLOGY, VOL. XXY. 47 



