58 



aquatic JHU 



pending increase by the greatly distended 

 abdomen. When this stage has been 

 reached the female should be placed alone 

 in a small aquarium containing quite a 

 mass of plants, which should be grouped 

 at the bright or window-side. The tank 

 should be frequently examined, and when 

 the young have been expelled the parent 

 should be removed. Daphnia and the 

 foods usually supplied tropical fishes 

 should be used. The temperature should 

 average from 70 to 75 degrees. 



Classification of Fishes 



DAVID G. STEAD, F. L. S. 



For purposes of reference, fishes — 

 which belong to a class called by Natural- 

 ists Pisces — are separated into two main 

 sub-classes known as Blasinobranchii and 

 the Teleostomi; with a third and smaller 

 one called Dipneusti or Dipnoi; the latter 

 including the remarkable lung-fishes. 

 These sub-classes are again divided into 

 orders, sub-orders and many families; 

 the families themselves being split up 

 into genera and species; the genus and 

 species forming what is called the scien- 

 tific name. For instance, in the case of 

 the Nannygai, the scientific name is 

 Beryx affitiis; the former being the genus, 

 and the latter the species. Fishes having 

 certain slight affinities with one another 

 are grouped together under the main di- 

 visions, while those showing a greater 

 and still greater natural relationship to 

 one another are placed in the more re- 

 stricted groups. Generally speaking, this 

 is the plan followed by all Zoologists and 

 Botanists in classifying animals and 

 plants ; the idea being to make the system 

 of classification as natural as possible, 

 and as far as possible obviating the 

 formation of artificial divisions. ortun- 

 ately, however ardently a person may 

 desire it, the latter cannot alwavs be car- 



ried out in practice ; in many cases, 

 through our imperfect knowledge of the 

 groups that we are dealing with. This 

 being so, scientific nomenclature is likely 

 to, and does, change in accordance with 

 the state of our knowledge. 



Incidentally, I might here mention, 

 that a great many people find it difficult 

 to understand the utility of technical 

 names for animals and plants ; and I here 

 take an opportunity of giving a suitable 

 answer. In doing so, I cannot do better 

 than quote the words of Professor Hux- 

 ley, who, in his work on "The Crayfish," 

 says: "Many people imagine that scien- 

 tific terminology is a needless burden im- 

 posed upon the novice, and ask us why 

 we cannot be content with plain English. 

 In reply I would suggest to such an ob- 

 jector to open a conversation about his 

 own business with a carpenter, or an 

 engineer, or, still better, with a sailor, 

 and try how far plain English will go. 

 The interview will not have lasted long 

 before he will find himself lost in a maze 

 of unintelligible technicalities. Every 

 calling has its technical terminology ; and 

 every artisan uses terms of art, which 

 sound like gibberish to those who know 

 nothing of the art, but are exceedingly 

 convenient to those who practice it. 



"In fact, every art is full of concep- 

 tions which are special to itself ; and, as 

 the use of language is to convey our con- 

 ceptions to one another, language must 

 supply signs for those conceptions. There 

 are two ways of doing this ; either exist- 

 ing signs may be combined in loose and 

 cumbrous periphrases, or new signs, hav- 

 ing a well-understood and definite sig- 

 nification, may be invented. The practice 

 of sensible people shows the advantage 

 of the latter course ; and here, as else- 

 where, science has simply followed and 

 improved upon common sense." 



