36 



KNOWLEDGE 



[FtBRCAEY, 1903. 



a comparison of photographs taken in 1892 and 1!HI2, but 

 the motion was in a contrary direction. It is not impossible, 

 however, to reconcile these seemingly opposed results. — 



Botanical. — The last volume of the Annales du Janlin 

 Botanique de Buitenzorg contains a paper by Prof. O. 

 Penzig on the Hora of Krakatoa. This, and a paper 

 published by Dr. Treub in the seventh volume of the 

 Annales, are especially interesting as throwing some light 

 on the question of the origin of insular floras. Krakatoa 

 lost all its vegetation in the terrible volcanic eruption of 

 August, 1883, which covered the island to a depth varying 

 from one to sixty metres with a bed of red-hot ashes and 

 pumice-stone. Its appearance afterwards, according to 

 Dr. Treub, was that of a mountain isolated in the sea, 

 rising with almost perpendicular sides to a height of 2-500 

 feet. The island, which is 21 miles from Java and 20 

 from Sumatra, was visited by Dr. Treub in 188(3. He 

 found it uninhabited, and not easily accessible. On the 

 narrow beach he found fruits or seeds of 7 species of 

 phanerogams, and young plants of 9 species, all the latter, 

 excepting one grass (Gijrnnothrie elegans), being the usual 

 littoral plants of tropical islands. lu the interior the 

 vegetation was quite different — ferns, both in the number 

 of species and individuals, predominating. Dr. Treub 

 concluded that ferus in such a flora precede and prepare 

 the soil for a phanerogamic vegetation. Their minute 

 spores would be brought long distances by the wind, but 

 it was remarkable that these would germinate and develop 

 into plants on the intensely arid soil of Krakatoa. A 

 close examimition of the ashes and pumice-stone, how- 

 ever, revealed the presence almost everywhere of Algse 

 (Cyanophycese), coating the soil with a thin gelatinous 

 layer in which the fern-spores would find a suitable place 

 for germination. Besides lower cryptogams. Dr. Treub 

 found, in 1886, 15 phanerogams and 11 ferns. Prof. 

 Penzig's ])aper records a visit to the island in 1897, made 

 by himself. Dr. Treub, and other botanists. The flora 

 consisted at that time of 62 species (.50 phanerogams and 

 12 vascular cryptogams) belonging to 24 orders. 1 he 

 ferns still predominated in the interior, and several species 

 of tall grasses formed a striking feature of the vegetation. 

 Seeds or fruits of 30 species were found on the beach, and 

 here and there seedling plants, showing that the seeds 

 were capable of germination. Of the -53 phanerogams. 

 Prof. Penzig estimates that 17 were introduced by the 

 agenev of the wind, 32 bv water, and 4 bv birds. — S. A. S. 



Zoological. — In a paper on the larvae of the various 

 species of eel, published in the Transactions of the Ameri- 

 can Philosophical Society, Mr. C. H. Eigenmann discusses 

 the question whether these fishes ever breed in fresh water. 

 Till eggs are actually taken in lakes the question must 

 remain suh judice, for, as the author very pertinently 

 remarks, the fact that eels are found in land-locked basins 

 cannot be regarded as an absolute proof that thev breed 

 there, although it is difficult to see how they can continue 

 to exist in such situations without doing so. 



A small fish from the rivers of West Africa, measuring 

 about three inches in length, and jjrovided with elongated 

 pectoral fins, is in the habit of taking aerial flightsaffer 

 the fashion of the true flying fish and flying gurnards. 

 This fish {Pantodon buchohi) is the only freshwater 

 species known to possess powers of this nature. Although 

 allied to the Osteoglossidie, it is regarded as the repre- 

 sentative of a special family — the Pantodontidw. A 

 reproduction of a photograph of this remarkable fish has 

 been recently published by Mr. G. A. Boulenger in The 

 Field. In the same journal that gentleman describes an 



unusually large kind of tadpole from South Africa, 

 measuring five inches in length. Here we may take the 

 opportunity of correcting an error in our December 

 " Notes " column, where the original description of the 

 marine representative of the genus Galaxiag was accredited 

 to Mr. Boulenger instead of to Captain Hutton. The 

 specimen on which the determination is based was found 

 in the mouth of a larger fish taken off Auckland. 



An important memoir on the true seals of the North 

 Pacific and Bering Sea has been recently published by 

 Dr. J. A. Allen in the BuUetin of the American Museum. 

 Perhaps the most generally interesting portion of this 

 communication relates to the difference between the 

 dentition of the male and female of the common seal. 

 In the latter sex the teeth are much smaller than those of 

 the male, and are inserted more obliquely in the jaw ; 

 they also differ by the reduction in the size and number of 

 the accessory cusps, which are almost invariably absent on 

 the inner side. The author recognises a considerable 

 number of species of Pacific seals, some of which might, 

 however, be regarded by other naturalists rather in the 

 light of local races. 



In a communication recently published in the Revista of 

 the La Plata Museum, Dr. E. Lehmann-Nitsche doubts 

 the possibility of the survival in South America of the 

 Patagonian ground-sloth, of which the remains were found 

 in such fresh condition in the weU-known cavern at Ultima 

 Esperanza. He believes the reports of its existence at 

 the present day to be based on other animals — notably 

 the otter. In the same journal. Dr. S. Both describes the 

 remains of other mammals found in association with those 

 of the ground-sloth. Among the most interesting of these 

 is the skull of a large jaguar (Felis listai). half as big 

 again as that of the living species. The author also 

 describes and figures the foot-bones of four species of 

 extinct American horses, one belonging to the genus 

 Eqiiug, a second to Hippidium, and the other two to 

 Onohippidium. The latter are characterized by their 

 extreme shortness ; and if, as appears to be the case, the 

 lateral toes were wanting, Onohippidium seems to have 

 liecome monodactyle independently of the true horses, 

 since its skull is quite different from those of the latter. 

 This is a matter of extreme interest, to which South 

 American palaeontologists might well devote special 

 attention. 



Hitherto only a single form of the African aard-wolf 

 {Proteles cristatus) has been recognised by naturalists. In 

 a recent issue of Noviiates Zoologiae the Hon. Walter 

 Rothschild has shown that three local races exist, namely, 

 the typical Cape form, the Angola form, distinguished by 

 its rufous colour and fewer stripes, and the Somali race, 

 characterised by its creamy-white ground-colour and 

 possibly by its small size. 



Since the year 1894, Mr. Rothschild has published from 

 time to time, in Novifates Zoologies, a series of most 

 valuable and interesting notes on giant land-tortoises, 

 mainly based on the specimens in his own collection at 

 Tring and in the Zoological Gardens. One of the most 

 important determinations made by him is the fact that 

 the celebrated Port Lewis tortoise, commonly known as 

 Marion's tortoise, originally came from the Seychelles, 

 and that it typifies a distinct species, Testudo sumeirei, 

 characterised, among other features, by the absence of a' 

 nuchal shield. During the past year three papers on 

 giant tortoises — one by Dr. A. Giinther, and two by Mr. 

 Rothschild — have appeared in the journal already named. 

 In the first of these Dr. Giinther describes the shell of a 

 tortoise from Charles Island, in the Galapagos group, 

 which had been made the type of a new species {T. 



