July 29, 1875] 



NATURE 



249 



these branches from one another has, first of all (and we 

 think with no exaggerated estimate of the gap to be 

 marked out), removed the Leptocardii altogether from 

 association with the other fish, and not only from associa- 

 tion with them but from association with the remaining 

 classes of Vertebrates. They stand alone as the group 

 Acrania, whilst the remaining Vertebrata are the Craniata. 

 The five remaining groups of Miiller's fishes find their 

 place with the Craniata, but one group is separated 

 within that large division as having no jaws, no hmbs, 

 and an unpaired nostril ; these are the Cyclostomi, which 

 are placed by Haeckel apart from all the remaining 

 Craniate Vertebrates. The steps of structural difi"erentia- 

 tion which must be passed through to connect the 

 Lampreys with the lowest of the remaining groups of J. 

 Miiller's Pisces seems to warrant this. They, the Dipnoi) 

 Ganoidei, Selachii, and Teleostei, all belong to the large 

 division of the double-nostrilled, jaw-bearing Craniata ; 

 but Haeckel cannot feel that the logic of his method is 

 fully carried out, if he does not mark more emphatically 

 the divergence of the structural characters of Dipnoi from 

 those of the remaining and dominant classes of Fish. 

 The class of Fishes is restricted to the three sub- classes of 

 Selachii, Ganoidei and Teleostei ; of which the first are 

 the nearest representatives of the common ancestors of 

 the Ganoidei and Teleostei, whilst the Dipnoi form a 

 separate class of the Gnathostomous Craniate Vertebrata, 

 reaching well forwards in the direction of the Amphibia, 

 which were derived from Paleozoic Dipnoi, these in turn 

 having been derived from Ganoidei. No doubt, it would 

 not be possible to make any distinction between the 

 ancestral Ganoidei and Dipnoi of Palaeozoic times, had 

 we them all before us ; but that is no reason why, in 

 framing our classifications, we should not use such breaks 

 and divisions of groups as will best indicate in the 

 tabular form the branching relationships of these and 

 neighbouring organisms. The consideration of a case 

 like the one just discussed renders it very obvious that 

 the whole method and point of view of the naturalist who 

 attempts to make classification the expression of the most 

 important laws of organic structure, and therefore a 

 genealogy, is different from that of the naturalist who 

 endeavours to make his groups as few as may be con- 

 venient, and such that a large number of propositions can 

 be affirmed with regard to them. The work of the latter 

 is marred by adhesion to a conventional form, that of the 

 former is inspired by a life-giving theory. 



The absence of illustrations to Prof. Carus's " Hand- 

 buch " is not to be considered as a deficiency. In the 

 first place, adequate illustration would immensely in- 

 crease the price of the work ; in the second place, we 

 have already the " I cones," which may serve excellently 

 as an atlas for much of the second volume. "What we 

 want now from Prof. Carus is another volume of "Icones," 

 to contain illustrations of the Vertebrata. 



E. Ray Lankester 



OUR SUMMER MIGRANTS 



Our Stirnmer Migrants. By J. E. Harting, F.L.S., 



F.Z.S. (Bickers and Son, 1875.) 



AMONG the many detailed differences between the 

 lives of country and town residents there is one 

 which has a marked influence on the lines of thought 



adopted by each. The townsman as a rule finds that his 

 numerous avocations — more numerous as they must be 

 to enable him to survive in the severer competition for a 

 livelihood that is associated with the extra expense in- 

 volved in a non-rural life— give him but little time or 

 need for simple physical exercise as such. He has to 

 form his ideas of the outside world by noting, as he 

 passes through various thoroughfares, such things as 

 attract his attention whilst he is on his way from one 

 duty to another. When his work is over, his great idea is 

 rest. The animated creation, humanity excepted, is a 

 sealed book to him. The case of the country resident is 

 very different. Either his slow-moving occupation in the 

 open air allows him ample opportunity for looking around 

 him, or he is compelled to "take a walk" in order to 

 overcome the injurious influence of a sedentary employ- 

 ment. The charms of scenery soon, from frequent repe- 

 tition, lose much of their fascination, and the observation 

 of the surrounding changes continually occurring in the 

 animated world become the chief objects of attraction. 

 Of these none are more interesting than the movements 

 of the birds, especially of those species which, instead of 

 taking up their continuous abode with us, only condescend 

 to visit our shores during those seasons of the year which 

 best suit their delicate constitutions. These, our summer 

 migrants, form the subject of the work before us ; one 

 which will be particularly attractive, as here presented, to 

 all who have any predilections towards ornithology or the 

 observation of natural phenomena, both on account of the 

 valuable information it contains and the particularly 

 elegant way in which, both typographically and as far as 

 binding is concerned, the book has been brought out, and 

 Bewick's accurate engravings have been reproduced. 



Mr. Harting's object has not been to write a systematic 

 work on the subject for beginners, but to collect the 

 results of his own and other more recent observations, 

 both as to the exact dates of arrival and departure of the 

 migratory species of our avifauna, as well as attested 

 facts with reference to the localities which they inhabit as 

 their winter- quarters. Prof. Newton's new edition of 

 " Yarrell's British Birds," Colonel Irby's " Ornithology of 

 the Straits of Gibraltar," and the investigations of the 

 late Mr. Edward Blyth, are amongst the most important 

 sources from which the author is enabled to collect the 

 observations which he classifies and employs so as to 

 make them of special interest with regard to each indi- 

 vidual species. 



The controversy, not long ago revived, and carried 

 on partly in this journal during 1869 and 1870 by 

 Prof. Newton, concerning the eggs of the Cuckoo, 

 makes the chapter devoted to that bird of special 

 interest. On the subject of whether the hen bird is 

 in the habit of always laying her eggs in nests of 

 the same species of foster parent. Prof. Newton re- 

 marks (Nature, vol. i. p. 75), "without attributing 

 any wonderful sagacity to the Cuckoo, it does seem 

 likely that the bird which once successfully deposited 

 her eggs in a Reed Wren's, or a Titlark's nest (as the 

 case may be) when she had an egg to dispose of, and 

 that she should continue her practice from one season to 

 another. We know that year after year the same migra- 

 tory bird will return to the same locality, and build its 

 nest in almost the sam^ spot. Though the Cuckoo be 



