270 



NATURE 



[January 19, 1893 



A. antennina, L., stems clustered, usually simple ; hydrothecse 

 separated by 2 joints. 6 to 9 in. high. Gen. distr. deep w. 



A. ramosa, Laml<., stems single, usually branched ; hydro- 

 thecjE separated by i joint only. 6 to 9 in. high. Gen. distr. 

 deep w. 



Now there are no nematophores along the stem, but only on 

 the pinnas ; A. ramosa may sometimes grow up unbranched, but 

 I for one never saw it so, and A. antennina is always simple, 

 save by the rarest individual abnormality ; the dimensions are 

 quite inaccurate, for we have A. antennina here of ail sizes up 

 to 24 inches high. The distribution given is too vague. In the 

 report of the B.A. Committee, which Prof. Herdman goes by, 

 deep water is defined as that below 100 fathoms ; but these two 

 are not deep-water species, either in that or any other common 

 use of the phrase. The authorities are very loosely given. A. 

 antennina, L., should be (L.), and if the bracketed authority, 

 i.e. the original user of the specific name, is to be the one quoted, 

 then for A. ramosa, I think Lamk. should give place to(Lamx.), 

 And why is the authority for the genus left out altogether? 



Moreover, even if these definitions were verbally accurate so 

 far as they go, they would only suffice to exclude one another, 

 with no reference to other non-British species. They are rather 

 definitions of groups of species or sub-genera, than of these two 

 particular forms. It would not matter very much, perhaps, in 

 this case, where other species are not likely to turn up upon our 

 coasts ; but such definitions, drawn with reference only to known 

 British forms, would soon lead to hopeless confusion in the case 

 of less-known groups. D'Arcy W. Thompson. 



Dundee, January II. 



On an Abnormality in the Veins of the Rabbit. 



Amongst a number of rabbits dissected in my laboratory 

 last term, one specimen exhibited a peculiarity in the venous 

 system which is especially interesting in connection with 

 Hochstetter's and Macalister's accounts of the development of 

 the veins. Unfortunately the specimen had been too far dis- 

 sected before the abnormality was noticed to follow out every 

 detail. 



The blood from the hinder extremities, urinogenital organs, 

 and abdominal walls, passed into a large vessel having the 

 position and relations of a postcaval posteriorly. Instead, 

 however, of passing through the dorsal border of the liver to | 

 penetrate the diaphragm, it was seen at the anterior part of the 

 abdomen to correspond to the azygos, receiving the superior 

 intercostal veins, and opening into the right precaval. This vessel 

 evidently, then, corresponded to the persistent right posterior 

 cardinal . The portal system was apparently normal, and the 

 hepatic veins opened into a postcaval, which extended through 

 the diaphragm to the heart in the usual manner. 



Thus the independently-formed section of the postcaval 

 {Leberabschnitt) had taken on no connection with the part 

 developed from the cardinals {Urnierenabschnitt), but had 

 remained as a separate vein, bringing back the blood from the 

 alimentary organs (and ? diaphragm) only. 



I have not thought it necessary to do more than mention these 

 facts, as the whole question has recently been fully discussed by 

 Dr. A. Robinson ("Abnormalities of the Venous System and 

 their relation to the Development of Veins," " Studies in 

 Anatomy from the Anatomical Department of the Owens 

 College," vol. i. p. 197, Manchester, 1891). The above case, 

 however, supports the view that the renal veins are direct tri- 

 butaries of the right cardinal, and not of the postcaval ; while 

 the reverse conclusion is derived from Dr. Robinson's obser- 

 vations. W. N. Parker. 



University College, Cardiff, January 14. 



Difficulties of Pliocene Geology. 



You were good enough to print a letter from me a week or 

 two ago, in which I called attention to some of the difficulties 

 in explaining the distribution of the so-called Pliocene beds. I 

 should like to prosecute the subject a little further. 



The geographical distribution of the mastodon is assuredly one 

 of the greatest paradoxes in natural science. 



As is well known, it occurs both in North and South America, 

 and on both sides of the Rocky Mountains and the Andes. It 

 has not occurred, however, so far as I know, north of the great 

 lakes in the east, nor of Oregon in the west, nor has it ever been 

 reported from Alaska, where mammoth remains are so abundant. 

 I do not know any evidence that it has been found anywhere in 



NO. 12 I 2, VOL. 47] 



Asia, north of the Himalayas, neither in China, nor Manchuria, 

 nor Mongolia, nor Turkestan, nor in Siberia ; nor has it occurreft 

 in European Russia, except close to the Black Sea, nor in Poland, 

 nor in Scandinavia, nor in North Germany. 



In the Old World its zone of distribution extended from India 

 to the Pyrenees, including the Mediterranean borders, the 

 valleys of the Danube, and the Middle Rhine, Eastern Eng- 

 land, and perhaps Iceland, whence some teeth are said to have 

 been sent to the royal collection at Copenhagen. This distri- 

 bution of a very highly specialized beast is certainly most extra- 

 ordinary. Granted that the mastodons of Western Europe and 

 those of America are slightly different, the difference is so slight 

 that, as Falconer says, Cuvier treated them as the same species, 

 and they cannot have been very long isolated. Yet how are we 

 to explain the facts, and do justice to the widespread view that 

 the ocean areas are very old ? 



It seems to me as clear as anything can be that when the 

 mastodon was distributed over Western Europe and America, 

 there must have been a land communication between the two 

 areas, and I cannot see how, with the facts before us, we can 

 escape the conclusion that this connection must have been across 

 either the Atlantic or the Pacific, not in high but in low lati- 

 tudes, perhaps across both. 



The mastodon is not the only animal which points the same 

 lesson. The machairodus, a very highly specialized feline, has 

 been found both in the Old and the New World, but did not 

 inhabit the great palaearctic province of Europasia, east of 

 the Rhine, nor America north of the great lakes. The Ameri- 

 can jaguar, a mere variety of the Old World leopard, is another 

 animal with the same abnormal distribution, so are the American 

 and the Old World tapirs. 



Now this connection between the Old and the New World 

 cannot, so far as we can judge, have been in high latitudes, for 

 the forms in question have not occurred in high latitudes. If 

 the connection had been across the Northern Pacific, we should 

 have had some remains of these animals in Japan, where more 

 than one fossil elephant has occurred ; or in the Sandwich islands, 

 which are, to all appearances, a very old land-surface. 



The connection must, therefore, if it was across the Pacific, 

 have been across its more equatorial part. It seems similarly 

 to follow from the absence of these animals in the high latitudes 

 of America and Europe, save the doubtful case of Iceland, that 

 in the case of the Atlantic also the land-bridge must have been 

 further south, and perhaps where the Atlantic islands still re- 

 main. One more inference. If there was a penannular or 

 circular belt of land about the earth in the tropical or sub- 

 tropical zone over which these beasts could travel, it would pos- 

 sibly account for the tertiary climate of high latitudes having 

 been a warm one, as we know it was. A zone of land in the 

 tropics would act as a furnace, whose heait would be widely dis- 

 tributed by the ocean currents in contact with it. 



The views here urged, it will be said, are like those of the 

 advocates of a Miocene Atlantis. They are in essence very 

 different, and meant to explain a very different phenomenon, 

 namely the aberrant and abnormal distribution of the mastodon 

 and its companions. The mention of the Miocene Atlantis, 

 however, suggests another and more critical difficulty in explain- 

 ing the Pliocene beds, but this must be postponed to another 

 letter. Henry H. Howorth. 



The Athenaeum Club, January 13. 



Earthquake Shocks. 



A SERIES of slight earthquake shocks have lately occurred in 

 this district, viz. January 3, 2.15 p.m.atSevern Junction(E.J.L.) 

 January 4, 11 a.m., Itton Court, Chepstow (a heavy plant; 

 in a greenhouse was seen to move four times by Mr. J. Curr 

 and the Rev. N. S. Barthropp) ; January 5, between 2 and 

 p.m., and again on the 6th (a little earlier), Llanthony Monastery 

 (a rumbling noise on the Black Mountains near the monastery 

 Mr. P. E. Hill) ; January 14, 6.55 p.m., a shock lasting mo r 

 than a second, Bigswear House, Coleford, Mr. J. V. Newbery 

 (Mr. Newbery has had experience of earthquakes, from a long 

 residence in Japan). E. J. Lowe, 



Shirenewton Hall, Chepstow. 



The Weather of Summer. 

 I REGRET to find that, in making a quotation at the end of 

 my letter last week (p. 246), I erred in supposing Mr. Symons 

 to be the writer. I beg to apologize for the slip. A. B. M. 



