174 MR. LUBBOCK ON SOME OCEANIC ENTOMOSTRACA 



not merely as artificial helps to classification, but as actual groups between wbicb no 

 links are known or will ever be discovered, I have already pointed out certain species 

 wbicb seem to prove the incorrectness of tbis opinion, and I shall have occasion in the 

 present paper to describe more than one species apparently intermediate between two 

 o-enera. Indeed, so far from considering such links as rare, it would be more correct to 

 say that every species is a link between other allied forms. The same argument is ap- 

 plicable to species. Of course, as long as any varieties remain imdescribed there will be 



gaps which, however, exist only in our knowledge, and not necessarily in nature. How 



many centuries must elapse, even under the most favourable circumstances, before all the 

 existing animals are known to us ; and even then how small a proportion will be described 

 of the animals which have peopled the world during the countless ages of past time ! How 

 worthless, then, is the argument against the mutability of species which depends on the 

 supposed absence of " links !" When every variety which now exists, and every one which 

 ever has existed, is known, then, and not until then, can this argument be considered con- 

 clusive. Moreover, it is admitted by every one that there are certain species which are 

 especially variable, that is to say, which present two or more extreme forms, with all the 

 intermediate gradations. Now we may fairly ask those who assert that no two species 

 are connected by links, how they would separate the instances of variable animals 

 (which they admit to occur) from the case which they say does not exist. If we were to 

 obtain to-morrow all the links between any two species which are now considered distinct, 

 no one can deny that the two would at once be united, and would hereafter appear in our 

 classifications only as one variable species. In fact, therefore, they first unite into one 

 species all those forms, hoAvever different, between which a complete series of links is 

 known, and then argue in favour of the permanence of species because no two of them are 

 united by links. 



As bearing on this point, I may also mention that there are in the collection about 

 ten or twelve other species, represented each by very few (perhaps only one or two) speci- 

 mens, which I can neither refer with sufficient confidence to any already known, and 

 which yet differ so little that I cannot venture to describe them as new. I have there- 

 fore put them aside for future examination, either when I have more specimens for 

 examination, or when the old species in question are better known. I do not see what 

 else I could have done; but in this way, no doubt, it comes to pass that specimens 

 which can be decidedly determined are named, and the doubtful forms, in which perhaps 

 many interesting series of links lie concealed, are left for re-examination at that more 

 " convenient season " to which naturalists, like other people, are only too apt to defer any 

 inconvenient duty. 



A good example of an intermediate form is presented to us by the species which I have 

 named Calanus latus. This species possesses some of the characters of Euch(sta, and 

 others (more numerous) which induced me to place it in Ccdanus. The maxillipeds 

 resemble those of Eucliceta, and are quite unlike the form which prevails in the immense 

 majority of Calani. The long setse with which the anterior antennae are provided, and 

 the long seta at the apex, are also similar to those of Biiclmta ; but, on the other hand, 

 the form of the front part of the cephalothorax, and the absence of long caudal setae. 



