94 Annals of the Carnegie Museum. 



The genera defined or accepted in this paper are largely based upon 

 the variously arranged hooks and barbs at the tip of the modified 

 anal fin of the male and the arrangement and shape of the teeth. 

 Dr. Eigenmann (1907, p. 425) first used the former characters in 

 defining genera of Poeciliids. He examined microscopically the anals 

 of a number of species, and among others based the genera Phal- 

 loceros and Phalloptychiis on these characters. The study of the anal 

 has been greatly extended in a recent paper by Mr. C. T. Regan (c. 

 1913),^ who revised all of the Poeciliince. The examination of the anal 

 is somewhat tedious. The anal of the male must be mounted in 

 damar, or balsam, and studied with a compound microscope. Un- 

 questionably, however, such procedure demonstrates true relation- 

 ships, and no new species should be described without an examination 

 of the anal. These characters are small since the males of these fishes 

 are among the least of vertebrates. Were these fishes larger in size 

 and easily examined, these characters would long ago have been 

 used in generic descriptions. It will be unfortunate, however, if this 

 system should lead to needless multiplication of genera. Some of 

 the closely related genera already recognized by Regan should prob- 

 ably be united. 



Within recent years these little fishes on account of their bright 

 colors and interesting habits have been extensively introduced as 

 aquarium fishes, especially into Germany. Various popular accounts 

 have appeared in some of the fanciers' journals, such as the " Wochen- 

 schrift Aquarien-Terrarienkunde " and the " Blatter Aquarien-Ter- 

 rarienkunde." These have not been accessible to me. In a contri- 

 bution from the Zoological Institute of the University of Berlin, Erich 

 Philippi, {d. 1908) has reviewed the more significant of these notices 

 and has added extensive observations of his own. Of this very thorough 

 paper I have given considerable summaries in English, particularly 

 of the parts dealing with the breeding habits. Philippi reared and 

 observed in the aquarium two species, Phalloceros candomaculatiis 

 and Cnesterodon decem-maculatus. In his account the former is 

 constantly spoken of as Glaridichthys {Phalloptychiis) januarius. 

 But he did not have and did not know P. januarius, and his systematic 

 deductions are therefore quite in error. 



In a number of instances observations, especially in regard to the 

 development and differentiation with age, number of young, etc., are 



2 The reference is to the bibliography of the subject which is given on p. 107. 



