THE AQUARIUM BULLETIN 



composing them, and so on. In the 

 fish shown in Figure 1, their number 

 and arrangement may be said to be 

 typical of the average teleostian or 

 bony fish. 



With respect to describing them 

 for our note-book, the details under 

 all of the above named heads should 

 be entered. First note that the fins 

 may be of two kinds, namely the 

 vertical or unpaired ones, as the 

 dorsal fin ((/. /. ), the post dorsal fin 

 ipd. /. ), the caudal fin (r. /. ), su])- 



ray, as in (/. /., and branched ray, as 

 in V. f. ; the last two are "soft rays." 

 Sometimes the ventral fins are united, 

 as we find them in fishes of the genus 

 Gohiiis. In the Catfishes, the spine of 

 either pectoral fin may be locked at 

 will, standing straight out from the 

 side ; there is a poison gland connec- 

 ted with it in some species of this 

 family, so that a painful and trouble- 

 some wound may be inflicted by the 

 form so armed. 



There is an enormous variation in 



,.^. ■?• 



•"^v. 



?)^I)!^rriCAK>"M' 



Fiu'. 3. Ri.uht lateral view of the comijlete skeleton of the HoR'fish or Capitaine 

 (Lachiiolaiiiin inaxiinus) ; reduced. Photogiaphed b> the author; the specimen prepared 

 by him at the New York Aquarium and now in his private collection. Bermuda. 

 Weiaht 12 lbs. 



ported by the caudal peduncle (r. /'.), 

 and the anal fin (a. /. ). On the other 

 hand the paired fins are the pectoral 

 fins (p. /. ), and the ventral one 

 (V. /.) 



Observe that the vertical fins are 

 arranged somewhere in the median 

 longitudinal plane of the body, while 

 the lateral fins are commonly J^laced 

 as shown in Figure 1. Particular 

 attention must be paid to the nature 

 of the rays composing the fins; these 

 are generally considered to be of four 

 kinds, as the simple ray, the spine 

 (Fig. 1., (/. /. ) ; the simple articulated 



the scales of fishes, or of those in such 

 species as have scales ; they not only 

 vary in the difli^erent kinds of fish, but 

 they vary all over the body of the 

 same individual. As a rule, they are 

 divided into two kinds, namely the 

 cycloid scales and the ctenoid scales. 

 Recently, Prof. T. D. C. Cockerell, of 

 the University of Colorado, has 

 written several extensive papers on 

 this subject, and has pointed out the 

 value of a detailed knowledge of fish- 

 scales, with respect to their use in 

 classification. 



(To be continued.) 



