298 



NA TURE 



ijMly 25, 1889 



borings surrounded by fossllifevous sand, just as described by Mr. 

 T. Mellard Reade from the Lancashire area. These stones are 

 generally limestones of various kinds — Carboniferous, Magnesian, 

 Jurissic, or Cretaceous — and the diversity of their origin seems 

 to show that they have first been scattered over a shallow sea- 

 bottom by floating ice, and afterwards perforated, but I do not 

 think that they can be taken as proof of the marine origin of 

 the boulder clay in which they now lie. 



The same boulder clay contains many detached valves of bi- 

 valve shells, and these very frequently still hold a pinch of sand 

 under the umbo, though themselves firmly embedded in hard 

 clay ; and in one ca^e I found, under such conditions, a perfect 

 shell ('Tellina halthicci), with valves united, enclosing similar 

 sandy material. 



It seems to me very difficult to explain by any theory of float- 

 ing ice how this sandy matrix could have been preserved in the 

 holes of the stones and under the valves of the shells, while it is 

 easy to understand how this might take place through the agency 

 of land ice advancing over a sea-bottom. 



Before the culmination of the glacial period, while yet the ice 

 was encroaching upon the sea-bed, and long before it had reached 

 its greatest extension, there must have been a vast quantity of 

 floating ice in the waters, which would drop stones and other 

 material over the sea-bottom ; and there must also have been a 

 great extrusion of matter from the various glaciers. And as the 

 ice advanced this material would necessarily become part of the 

 moraine profonde of the glacier, and would be more or less 

 mixed up with the old sea-bottom, but the resulting boulder clay 

 could scarcely be called marine. G. W. Lamplugh. 



Bridlington Quay, July 15. 



Mr. Lydekker on Phenacodus and the Athecae. 



In his article on Phenacochis primuzms in Nature of May 

 16 (p. 57), Mr, Tydekker expresses his disbelief in my opinion 

 that that animal is nearly related to the immediate ancestor of 

 the line of the Quadrumana, and of man. I am somewhat sur- 

 prised at the ]:;ositiveness of Mr. Lydekker's expression, as he 

 must be aware of the difficulties that still surround this part of 

 the question. What may be known about it is as follows : — 



First, I have always been careful to avoid the assertion that 

 the genus Phenacodus was in the direct line of descent of man. 

 When I first traced the ancestry of the Quadrumana, I indicated 

 the sub-order Condylarthra as its source {American Naturalist, 

 1885, p. 347; "Origin of the Fittest," 1887, p. 343), not the genus 

 Phenacodtis. On a subsequent occasion I restricted the range of 

 probable ancestry to the family PhcnacodontidcB {Naturalist, 

 1888, p. 663). In the advertisement to which Mr. Lydekker re- 

 fers, I say of the Phenacodus privicevus, " Representative of type 

 believed to be the ancestor of all hoofed Mammalia, monkeys, 

 and man." Mr. Lydekker's reference to this advertisement is 

 slightly different. 



Second, Mr. Lydekker objects to regarding Phenacodus as 

 within the ancestry of the lemurs and man, because it appears 

 to have no clavicle. To this proposition two replies may be 

 made. The first is, that it is by no means certain that it had no 

 clavicle. The second is, that if it had none it is not certain that 

 that fact would exclude it from the ancestry of the Quadrumana ; 

 certainly it would not exclude some near ally of the same family 

 or sub-order which possessed a clavicle. On these points I 

 remark further. 



Third, nothing can be determined from the specimens as to 

 whether the Phenacodus primcevus or P. wortmani had clavicles 

 or not. None were found, but this part of the skeleton was dis- 

 turbed in both specimens. Thus the clavicles, if present, may 

 have been like those of some Carnivora and Rodentia, connected 

 with the manubrium sterni and scapula by soft tissue only, and 

 so have been readily lost. 



Fourth, the presence or absence of clavicles is not important 

 in a systematic sense. It is not available as a definition in the 

 orders Edentata, Rodentia, Insectivora, and Carnivora, where, 

 as is well known, it may be present, rudimental, or absent. And 

 in the phylogenetic history of a line, I see no reason why clavicles 

 might not lose and later recover their osseous tissue under 

 suitable stimulation. 



Finally, I believe that the Condylarthra are in the direct line 

 of ancestry of the higher apes, so long as no better objections 

 can be found than those raised by Mr. Lydekker. Another ob- 

 jection exists which he has not pointed out ; viz. the absence of 

 anapophyses of the vertebrre. But this objection loses much 

 ,-)oi '. v'hen we remember that anapophyses are also wanting 



from the vertebra? of the anthropoid apes and man. What their 

 status was in the anthropoid lemurs {Anaptomorphiis) we do not 

 yet know. Moreover, a trace of the anapophysial structure does 

 exist in both species of Phenacodtts, as a fold continuous from 

 the posterior border of the neural arch over the centrum. As 

 regards the clavicle, it is highly probable that it is present in 

 some of the genera of the Condylarthra, and even of the Phcnac- 

 odontidm, such, for instance, as Protogonia, but we know too 

 little of the structure of the skeletons of feveral allied genera, to 

 enable us to determine the points in question. On the presence 

 or absence of anapophyses in such genus of Condylarthra will 

 depend the solution of the question whether the descent of man 

 passes through Anaptomorphus or Adapis, or some other un- 

 discovered form of Quadrumana, to the anthropoid apes. 



While on this subject I refer to Mr. Lydekker's reference to 

 my term Athecae (Testudinata), as " ungrammatical. " He de- 

 clares that the grammatical form should be Athecata. Now, 

 while the latter expression is perhaps grammatical, it is not more 

 so than the one which I elected to use. It is probably well 

 known to Mr. Lydekker that scientific names are written in 

 Latin, and not in Greek. The singular Atheca, although de- 

 rived from the Greek, becomes Latin by scientific use and usage, 

 and is declined, genitive ce, and nominative plural a: also. See 

 Latin words derived from 0rj«:r;, as Bibliotheca, -se. I used the 

 substantive form, which is more usual than the adjective, in 

 making scientific names. E. D. Cope. 



Philadelphia, July I. 



Systematic Position of the Characeae. 



The position in a natural system of classification of this small 

 and strongly-differentiated group of aquatic plants has been so 

 long a subject of controversy, that any additional light upon it 

 will be welcome to vegetable physiologists. I therefore desire 

 to call the attention of my fellow-botanists to the remarkable 

 paper by M. Guignard, "On the Development and Constitution 

 of the Antherozoids of Cryptogams," in the early numbers of 

 the new botanical journal edited by M. Bonnier — -the Kevuc 

 Generate de Botanique. It is true that these observations only 

 confirm the earlier ones of Thuret ; but the care with which M. 

 Guignard has worked out the subject, and his beautiful drawings, 

 tend to emphasize the results previously obtaintd. 



No one who compares the drawings of the antherozoid of Chara 

 fragilis in PL 2 with those oi Pellia epipiiylla in PI. 3 can fail to 

 be struck with their remarkable resemblance. Each is a long, 

 corkscrew- shaped body, with a pair of very long and slender 

 vibratile cilia attached to its anterior extremity. The mode of 

 development of the antherozoid is also the same in all essential 

 particulars in both cases, and is thus described by M. Guignard. 

 The body of the antherozoid proceeds from the nucleus of the 

 mother-cell, and moreover gives all the micro-chemical reactions 

 of nuclein. The vibratile cilia are derived from the cytoplasm. 

 A thickening band first appears on the surface of the nucleus, 

 and grows longer and longer, forming eventually a kind of beak, 

 and the whole nucleus becomes twisted spirally as it increases in 

 length. As soon as the outlines of the anterior extremity of the 

 filament are discernible, the two cilia may be perceived in the 

 thin layer of hyaline protoplasm which is nearest this extremity. 

 Later on, the cilia, which at first lie close to the filament, become 

 separated from it, and the rest of the protoplasm gradually dis- 

 appears, being absorbed and used up for the nutrition of the 

 antherozoid, so that only a few granulations are left on the 

 posterior extremity of the filament. The only difference of any 

 importance between the antherozoids of Characeas and thbse of 

 Muscinere is the absence in the former of a vesicle formed from 

 the cytoplasm of the mother-cell. 



If now this is compared with the figures (PI. 5) of the 

 antherozoids of Fucus serratus, and the account of their mode 

 of development, it will be seen how wide are the differences in 

 many essential points between the corresponding processes in 

 Charace;^ and in the higher Algre. These facts seem to me 

 strongly to corroborate the view which I have on several 

 occasions ventured to bring forward, and to support by other 

 considerations, that the Characeae are more nearly related to the 

 Muscineae than to the true Algae. 



I may mention in conclusion that M. Guignard adopts the 

 revised terminology which I have advocated, of antherozoid 

 instead of " spermatozoid " for the male fecundatin2r organs of 

 most Cryptogams, and of pollinoids (or T2,\\\tx pollinidcs) instead 

 of "spermatia" for the corresponding organs in the Florideae. 



Alfred W. Bennett. 



