66 



NATURE 



\_Nov. 1 6, 1876 



the genera Nassa, Natica, and Fusus. These investigations are 

 of special interest because, according to Prof. Ray Lankester, 

 they are the first in which the method of cutting sections has 

 been employed' in the examination of these minute eggs and 

 embryos. To have carried the conquests of embryology to such 

 an extent is no slight achievement. Histologists are VftW aware 

 that the estimate formed of structures by viewing them as trans- 

 parent objects' is liable to be erroneous, even in favourable cir- 

 cumstances ; much more so when the objects have an appreciable 

 thickness and are more or less opaque. In all cases it is desir- 

 able to obtain, if possible, confirmatory evidence by means of 

 sections cut through hardened specimens ; but the labour and 

 manipulative skill required are much greater than in viewing 

 bodies as transparent objects. At the same time Dr. Bobretzky's 

 results convey an instructive warning to those who are tempted 

 to generalise. Nothing is more common, or more detrimental, 

 than for a series of generalisations to be founded on a new set of 

 observations more or less limited in their range. By the con. 

 tinual discovery of fresh variations in the mode in which the ova 

 of aquatic animals are segmented, and acquire their embryonic 

 layers, it is to be hoped that students are being led to see that 

 nothing but summaries of observed facts are of real value at 

 present. Dr. Bobretzky seems to have made it evident that in 

 the genus Nassa the three primary embryonic layers are all esta- 

 blished during the segmentation of the ovum, and as a direct 

 result of that process ; and this is certainly a surprise. Again, 

 a definite relation has been made out in certain 'cases between 

 the orifice of the earliest invagination of cells and the permanent 

 mouth of the animal. It is to be regretted, however, that Dr. 

 Bobretzky throws doubt on Prof. Lankester's observations on 

 some genera of fresh-water Gastropods, in which facts [of a dif- 

 ferent character were discovered. However, the latter investi- 

 gator has been stimulated to examine the development of the 

 common Paludina vivipara anew, and has published an account 

 of it in'^the Quarterly journal of Microscopical Science for Octo- 

 ber last ; his previous assertions appear to be very definitely 

 confirmed, notwithstanding that the method of sections has not 

 been adopted : the embryos, it may be stated, are amongst the 

 most transparent in the Gastropod class. Although it must be a 

 disappointment to ardent theorists to find that they are so far from 

 a satisfactory goal, it may encourage young workers when it is 

 seen that the field for independent investigation is practically 

 unlimited, even in embryology. In invertebrates, at least, it 

 appears that the development of every genus should be studied^ 

 and that new facts bearing on evolution, on the distribution of 

 life, on the influence of external conditions, on the warping, so 

 to speak, of the direct process of development by temporary 

 influences' acting during embryonic life, will reward all diligent 

 work in this fruitful field. 



New Species of Echidna. — A very remarkable zoological 

 discovery is announced from Genoa. Among the collections 

 recently received by the Marquis G. Doria for the Museo Civico 

 of that city from Mr. Bruyu, of Ternate, is a specimen of a new 

 and large species of Echidtia^ from the Arfak Mountains of New 

 Guinea. As the only two Ornithodelphs hitherto known are 

 exclusively confined to Australia, it is difficult to over-estimate 

 the importance, as regards geographical zoology, of the existence 

 of a third member of this peculiar group of mammals in the 

 adjoining land of New Guinea. 



Sphenodon Guentheri.— At a recent meeting of the 

 Wellington Philosophical Society (New Zealand) Dr. Buller 

 described a second species of Lizard (if Dr. Giinther will allow 

 us to call it so) of the genus Sphenodon (sive Hatieria). Sphenodon 

 guentheri, as Dr. Buller proposes to designate this new form, 

 "after the greatest of living herpetologists," is from the Brother 

 Islands, whilst the original ^S". punctatus appear to be confined 

 to the Karewa Island, in the Bay of Plenty. 



A New Fish.— Dr. W. Peters has lately communicated to the 

 Royal Academy of Science of Berlin the description of a new fish 

 of the order Leptocardii. Of this most peculiar group of " Inverte- 

 brated Vertebrates," but one genus — the Aniphioxus branchio- 

 stoma — has yet been recognised, though several more or less 

 doubtful species of the genus from various parts of the world 

 have been described. Dr. Peters has received from Australia 

 several examples of a well-marked, though closely-allied, form 

 which he names Epigomethys cultellus, and which differs from 

 Branchiosto7}ia in having a high dorsal fin and in wanting the 

 caudal and anal fins. These minute rarities were dredged up 

 near Peale Island, in Moreton Bay, in eight fathoms water. 



A New Peripatus. — A paper on Peripatus, by Capt. 

 F. W. Hutton, Director of the Otago Museum, which will 

 be found to be a valuable supplement to that by Mr. H. 

 Moseley, in the Transactions of the Royal Society, has been 

 published in the current number of the Annals and Magazine of 

 Natural History. The author describes a new species, which he 

 names Peripatus novce-Zealandice, peculiar in being hermaphro- 

 dite. These strange animals, between i and 2 inches in length, 

 are found in the West Indies, Chili, the Cape of Good Hope, 

 and New Zealand. They have relations with worms and with 

 the tracheate Articulata, and habits much hke those of the wood- 

 louse. 



The Persian Deer. — In the same number of the same 

 journal. Dr. N. Severtzoff has also an interesting communication 

 on the affinities of the Persian Deer {Cervus maral), in which 

 he shows that this species is identical with the Wapiti [C. cana- 

 densis) of Canada, that from the warmer locality [changing colour 

 in the summer, that from the colder not doing so. The author 

 very reasonably suggests that the name C. wapiti or C. maral yjovXA. 

 be preferable to C. canadensis, now the distribution of the species 

 has been shown to be so general. 



Fishes of the Aralo-Caspio-Euxine Basin. — The re- 

 sults arrived at by Prof. Kessler, after many years' study of 

 the fishes of the Aralo-Caspio-Euxine region (which includes 

 these three interior seas with their affluents) are as follows : — The 

 number of described species is about 280, out of which 80 are 

 marine, 100 fresh- water, and 40 brackish water species ; 20 in- 

 habit various waters, and 40 are migratory. 150 species belong 

 exclusively to the region, and 10 have spread out into neighbour- 

 ing regions at comparatively recent times. Out of the 120 other 

 species, about 25 have a wide range of distribution, about 80 

 have migrated into the Black Sea from the Mediterranean, and 

 about 15 fresh- water species have penetrated into the Aralo- 

 Caspio-Euxine region from the north. Out of the 160 species 

 limited exclusively to this region, 45 were found in the Black 

 Sea, 54 in the Caspian, and 26 in Lake Aral. There are but 

 6 species which inhabit simultaneously the three basins of the 

 three interior seas, 4 species which are common to the Caspian 

 and Aral basins, and 25 to those of the Black Sea and the 

 Caspian. The most characteristic families of fishes in the region 

 are the Gobioidecc and the Acipenseridce, the former being repre- 

 sented by r j less than 50 species, out of which 40 do not extend 

 over other regions ; the genus Benthophilus of this family, which 

 numbers here six or seven species, has no representatives abroad ; 

 and the genus Scaphirynchus, represented in the Amu and Syr- 

 darya by three species, is known to have but one more species 

 inhabiting the Mississippi. 



Development of the Mamma. — Among the important his- 

 tological investigations which have appeared quite recently in one 

 by Mr. C. Creighton, M.B., in the current number of the y^«r«^/ 

 of Anatomy and Physiology, on the development of the mamma, 

 and of the mammary function, in which the view generally re- 

 ceived that the mamma is a complex extension downwards of the 

 ectoderm or surface of the skin, is combated in favour of the? 



