ZOOLOOICAT. SOCIETY lU l.I.KTIN 



Side anti front vie^^■ 



HALF-MOON FISH 

 1. Fiom a dead, mutilated specimen 



imported thence to this country, and was first 

 shown at the public exhibitions of the Brooklj'n 

 and New York Aquarium Societies during the 

 past fall. In December the New York Aqua- 

 rium was fortunate enough to secure four speci- 

 mens of this very attractive fish. 



The species was first described in 1831 from 

 Brazil and, although it has since been men- 

 tioned by a number of writers on South Ameri- 

 can fislies and is known to be widely distributed 

 in British Guiana and Brazil, little or nothing 

 seems to have been recorded concerning its hab- 

 its and general natural history. It is said to 

 be very common in the shallow waters of the 

 upper Amazon region and that they may be 

 most readily caught at night. So far as is 

 known, there is only one species in the genus, 

 which belongs to the family Cichlidae, a family 

 which in its general ecology replaces the bass 

 and sunfish family of North American waters. 



The half-moon fish reaches a length of a little 

 more than three inches, measured from the tip 

 of the snout to the end of the middle rays of 

 the caudal fin. It is very deep-bodied and quite 

 compressed, the height being several times the 

 thickness of the body. In color the body is 

 dusky above and silvery below. A distinct dark 

 bar e.\tends verticallv across the bodv through 



the eye, and a broader bar 

 runs vertically from the 

 front of the anal fin upward 

 1 to the front of the dorsal. 



I whence it is C(mtinued on 



I the dorsal (in. There is a 



I distinct dark vertical bar 



^ also at tlie base of the cau- 



^^k dal fin. Fainter dark bars 



^^^ are found between the dark- 



^^H rr ones and also on the cau- 



^^^H dal fin. The dorsal and 



^^^B anal fins are extended into 



^^H lo'ig filaments and lobes of 



^^m the caudal fin are also simi- 



^V larly extended. The pec- 



^V toral fins are unmodified. 



n\ but the venlrals are enor- 



mously extended into limg 

 wliite filaments. 



The species has a remark- 

 able ability for rapid change 

 of color and under excite- 

 ment the dark bars become 

 vividly and intensely black. 

 The change appears to be 

 practically instantaneous 

 and the normal coloration 

 may be resumed again with 

 equal rapidity. This change is so great and so 

 sudden as to be positively startling. 



As these fishes require very warm water they 

 are kept in a specially heated tank at a tem- 

 perature of about 75 degrees. 



The common name refers to the outline of the 

 body with the dorsal and anal fins and is quite 

 appropriate in the perfect adult fish. R. C. O. 



REMARKABLE RECOVERY OF A 

 WOUNDED FISH. 



IT is well known that many invertebrates liave 

 remarkable powers of regeneration so that 

 parts injured or removed by mutilation may 

 often be entirely regenerated. Take, for ex- 

 ample, the ordinary starfish, which can be torn 

 in two with the result that each of the parts 

 will eventually regenerate the lost organs, and 

 develop into two perfectly formed starfishes. 

 In some cases this may even go so far that a 

 single detached arm of the starfish will evolve 

 a wliole new body with the other arms. Among 

 vertebrated animals, however, this regenerative 

 power is confined as a rule to the healing of 

 wounds or to the redevelopment of comparative- 

 ly unimportant parts of the body. Observa- 



