FISHES OF FAMILY BLENNIIDAE 57 



are considered specialized. The caudal illustrated in figure 15b is 

 found in Hypleurochilus (Blenniini) , Omobranchus lini, and 0. anolius 

 (Omobranchini, but with simple rays only), Laiphognathus (Omo- 

 branchini) may also have the caudal type figured in figure 15b (fin 

 was damaged) , but the lower hypural plate is fused to the upper and 

 the rays are not branched. The caudal in figure 15c is found in Negos- 

 cartes, Salarias fasciatus, Astrosalarias (Salariini, the last-mentioned 

 genus with simple rays) , Enchelyurus (Omobranchini, but with simple 

 rays and the ventral hypural plate fused to the urostyle), and occa- 

 sional specimens of Meiacanthus, Runula, and Petroscirtes (Nemophi- 

 dinae, but all as variants only). The caudal illustrated in figure 15d 

 is found in all other Nemophidinae (except the ventral hypural plate 

 is fused to the urostyle in Xiphasia) , Hypsoblennius, Blennius nicholsi, 

 Chasmodes bosguianus (Blenniini, but with branched caudal rays), 

 Omobranchus loxozonus, 0. elegans, and 0. banditus (Omobranchini). 

 The latter type caudal appears to be the most specialized of the 

 blenniids. 



It is probable that the various types of blenniid caudals, except 

 the least specialized, have arisen several times within the various 

 suprageneric taxa, but trends are evident. As postulated on the basis 

 of jaws and dentition (q.v.), the Nemophidinae are derived either 

 from the Omobranchini or from a group that gave rise to the Omo- 

 branchini. This is supported somewhat by the caudal type (fig. 15d) 

 found in some Omobranchus species and the Nemophidinae (including 

 the fact that these two groups share in having only simple caudal 

 rays). That the Omobranchini are derived from the Blenniini is sup- 

 ported perhaps by the fact that some species of each group have the 

 type caudals illustrated in figures 15b and c. The Salariini were 

 postulated as being derived from the Blenniini, and the most primitive 

 type blenniid caudal is found only in these two groups. 



Dorsal fin. — The dorsal fin of all blenniids is composed of flexible 

 spines and segmented rays. The number of spines varies from four 

 (three in variant individuals) in some species of Meiacanthus to 17 

 in Lophalticus. The most frequent numbers of spines encountered 

 are 11 to 13. The number of spines is relatively constant for a genus 

 (Meiacanthus with three to 10 and Xiphasia with 11 to 14 are note- 

 worthy exceptions) or species but may vary plus or minus one spine. 



In many genera of the Blenniini and Salariini there is a tendency 

 to reduce the size of the posteriormost spine, and in some species the 

 spine is noticeable only in osteological preparations or on radiographs. 

 The reduction of the terminal spine seems to have developed inde- 

 pendently in many genera and is therefore of little significance in 

 determining relationships. The dorsal fin membrane usually is incised 

 at the level of the reduced spine (one notable exception: Ophioblennius) . 



