Nov. I, 18S3] 



NATURE 



Moseley, has a series of symmetrically placed nodular 

 cartilaginous thickenings in the otherwise thin and mem- 

 branous test. This Report of Prof. HerJman's may be 

 regarded as almost a monograph of the Tunicates, and is a 

 most valuable addition to our knowledge of this little 

 known group of forms. 



Volume VII. contains four Reports. The first of these 

 is by Prof. Morrison Watson, on the anatomy of the 

 SpheniscidK collected during the voj'a^e. The collec- 

 tion contained three or four adult specimens of each of 

 the species obtained, preserved for the most part in brine, 

 but in some instances in spirit, as well as a number of 

 immature birds taken from the nest, together with eggs 

 in various stages of hatching, preserved partly in spirits 

 and partly in bi.-hromate of potash. In the present 

 Report only the anatomy of the adult birds is treated of; 

 that of the young being reserved for a second part. 

 Selecting Eudyptes chrysocoiiie from Tristan d'Acunha as 

 a standard, the anatomy of the other seven species is 

 compared with it ; thus in every section the anatomy of 

 the standard species is given in detail, and then the 

 variations met with in each of the others is appended. 

 In those cases in which no variations are reported the 

 anatomy of the forms was identical. The descriptive 

 anatomy of the various systems of tissues seems to leave 

 little to future investigators to record. In the section 

 devoted to osteology, while treating of the bones of the 

 anterior extremity, the author remarks that in several 

 particulars the penguin's wing differs from that of other 

 birds — movements of pure flexion and e.Ktension in the 

 joints beyond the shoulder can scarcely be said to be 

 possible ; the articulations, however, admit of a very 

 ■considerable amount of rotation, and consequently, in- 

 stead of the limb being converted into an absolutely rigid 

 paddle or oar, the rotation in question converts the wing 

 into a screw-like blade, the curvatures of which are con- 

 stantly varying in accordance with the amount of rotation 

 which the forms of the different joints permit. Upon care- 

 fully watching a living specimen of Aptenodytes in the 

 Zoological Society's Gardens, the author observed that 

 the wing of the penguin is never used in the manner of a 

 rigid oar, which would imply the simultaneous movement 

 •of both wings in the same direction in order to propel the 

 bird. On the contrary, the wings were often and indeed 

 visually brought into use alternately, much in the same 

 manner as the pectoral fins of a fish, and in every move- 

 ment of the wing wiry, screw-like curvatures, which are due 

 to the rotation of the different segments of the limbs upon 

 ■one another, are strongly developed. In fact, a constant 

 screwing and unscrewing of the separate alar segments 

 upon one another takes place simultaneously with the 

 forward and backward movement of the organ as a 

 whole. 



From general considerations of the anatomy of the 

 penguin, Prof. Watson concludes that these birds together 

 form a natural group, every member of which is possessed 

 of certain anatomical peculiarities which serve at once to 

 associate it with its fellows and to separate it from the 

 members of other groups which may more or less closely 

 resemble the Spheniscid.'e. From an anatomical point 

 •of view he would recognise but three genera — Apteno- 

 dytes, Spheniscus, and Eudyptes. The remarks on the 

 •characteristics of these genera and the limits of the 



species contained in them are among the most interesting 

 in this Report. 



As to the phylogeny of the penguins the author con- 

 cludes that they form the surviving members of a group 

 which had early diverged from the primitive avian stem, 

 but that at the time when the separation took place, the 

 members of that stem had so far diverged from the primi- 

 tive ornithoscelidan form as to be possessed of anterior 

 extremities, which, instead of forming organs of terrestrial, 

 had become transformed into organs adapted to aerial 

 progression, or true wings. If this view be correct, 

 palaeontological research may, in the course of time, dis- 

 close the existence of Spheniscidine remains which may 

 enable us to trace the line of descent of the penguins of 

 the present day from the original avian stem, and through 

 it the relationship which exists between the modern 

 Spheniscus or Eudyptes, with their separate metatarsal 

 bones and aborted wings on the one hand, and the major- 

 ity of modern birds, with their conjoined metatarsal 

 bones and perfect wings on the other. 



The geographical distribution of these birds is of great 

 interest. They are entirely confined to the southern 

 hemisphere, none of them straying north of the equator. 

 Within this area their distribution is very extensive, 

 reaching from the Galapagos Islands on the equator, 

 southwards to the Antarctic Islands. Prof. Watson 

 surmises that this distribution does not depend on 

 temperature, but may depend on a relative abundance of 

 the food supply (Cephalopods and Crustacea) found in the 

 two hemispheres respectively ; but the editor, Mr. J. 

 Murray, in a footnote, says : " The penguins reach the 

 equator only on the coasts of Chili and Peru. Now the 

 Peruvian current from the Antarctic skirts along this 

 coast, and takes a low temperature as far north as the 

 Galapagos Isles ; the temperatiu-e of the sea being 

 there (equator) 62° to 66', while in the middle of the 

 Pacific (equator) the surface temperature is Sr to SS^. 

 Temperature, therefore, most probably has something to 

 do with the limitation of the geographical distribution of 

 the Spheniscidse." 



The second memoir is by Dr. F. Buchanan White, on 

 the Pelagic Hemiptera collected during the voyage. 

 These, the only truly pelagic insects, belong to the genera 

 Halobates and Halobatodes. The first of these was 

 founded sixty years ago by Eschscholtz for three species 

 taken during the well-known voyage of Kotzebue round 

 the world. But few species are known, and they are 

 very rarely to be found in collections, though they seem 

 to be abundantly distributed in tropical seas. Their struc- 

 ture would seem to indicate that they are archaic forms 

 of great antiquity, and as doubtless many species yet 

 remain to be discovered, it is to be hoped that some one 

 with the will and the opportunity will be found to turn 

 their attention to the group. In the meanwhile Dr. 

 White has in this Report given a detailed account of the 

 literature of these genera, followed by an account of the 

 anatomy and description of the genera and species. 

 Of the genus Halobates he describes eleven species, of 

 which three were first described by Eschscholtz, one 

 each by Templeton and Frauenfeld, and six for the first 

 time in this memoir. In his remarks on the species 

 we notice that, after a very bad fashion adopted by some 

 entomologists, these are alluded to under their trivial 



