24. MTJR^NA. 9o 



Sir John Richardson has divided the species of this genus into 

 smaller groups, distinguished by the dentition. Dr. Kaup has done 

 nothing beyond adopting these groups and attaching generic names 

 to them. However, only in a comparatively small part of the species 

 is the arrangement of the teeth of systematic value, as the dentition 

 changes to a considerable extent with age. Young examples have 

 generally more series of teeth than mature or old indiAaduals. Espe- 

 cially with regard to the one, two, or three large teeth forming an 

 inner maxiUary series, it appears that normally these teeth enter the 

 outer series as the age of the individual advances. This change is by 

 no means regular, and one or two inner teeth are sometimes found in 

 examples of considerable size. Further, in some species the biserial 

 arrangement appears to be persistent through life ; in other species, 

 which are known from a few examples only, we have no means of 

 judging of the extent of change. The uni- or biserial arrangement 

 of the vomerine teeth is also subject to much variation. In the 

 following synopsis the maxillary teeth are admitted to be biserial 

 only when the inner series consists of several (more than three) 

 teeth. 



Synoj)sis of the Subgenera and Species. 



I. Teeth acute. 



A. Posterior nostrils tubular : Murcena, p. 96. 



B. Posterior nostrils not tubular : Gymnothorax, p. 100. 



1. Body moderately elongate ; tail not (or not much) longer than 



the body; snout of moderate extent. 

 a. Ornamented by well-defined white (in spirits) spots or ocelli. 



a. Maxillary and intermaxillary teeth biserial, p. 100. 



/3. Maxillary teeth only biserial, p. 101. 



y. Maxillary teeth uniserial, p. 102. 

 h. Ornamented by well-defined black cross bands, p. 104. 



c. Ornamented by well-defined polygonal or round black spots. 



p. 106. 



d. Ornamented by yellowish lines forming a network, p. 110. 

 c. Body with dark or light markings, which are not well de- 

 fined and more or less irregidiir. 



a. Maxillary teeth biserial, p. 112. 



/3. MaxUlary teeth uniserial, p. 116. 

 /. Snout ornamented with brown longitudinal bands, p. 122. 

 g. Coloration uniform. 



a. Dorsal fin elevated, p. 122. 



^. Dorsal fin not elevated, p. 123. 



2. Snout slender, much elongate, p. 127. 



3. Exceedingly elongate, the tail being twice as long as the body 



{Thyrsoidea, Blkr.), p. 127. 



4. Exceedingly elongate, the tail being nearly as long as the body 



(^Strophidon, Blkr.), p. 128. 

 II. Moat of the teeth are obtuse, molar-like : Poecilophis, p. 128. 



