October i6, 1890] 



NATURE 



589 



of insects to the cavities, and have never been able to 

 detect any evidence of general distribution of pollen over 

 the stigmatic surface. Examination of individual flowers 

 has given like results ; in most cases it has been im- 

 possible to find any pollen within the receptacle or cavity, 

 and in the few cases in which any was found it was 

 represented by one or two shrivelled grains adherent to 

 the corpses of insects. It must be borne in mind, too, 

 that, if we accept the hypothesis that the development of 

 the embryos is due to ordinary processes of pollination, 

 we must assume not only that a single insect can convey 

 many thousands of pollen-grains with it in spite of the 

 excessive obstructions to access presented by the ostiolar 

 plug, but that these grains are also methodically and 

 economically distributed, for, unless each stigma were 

 only allowed to appropriate a single grain, the amount 

 introduced would have to be indefinitely multiplied. 



" The most important evidence against the occurrence 

 of pollination of any sort as a normal and essential event 

 lies, however, in the fact that the embryo originates, as it 

 does in undoubted cases of development, apart from 

 pollination. The embryo, as a rule — for of course it is 

 possible that pollination and normal evolution may occur 

 in certain individual flowers— certainly arises as an out- 

 growth of the nucellar parenchyma, outside the embryo- 

 sac, and not as the result of special evolution of any ele- 

 ments contained with in the latter. The embryo-sac up to 

 the period of insect-access and of initial development of 

 the embryo normally retains the characters of a simple 

 uninucleate cell. There is no evidence of the formation 

 of an oosphere, of synergidse, or of antipodal cells within 

 it, and it is only subsequent to commencing evolution of 

 the embryo that the primary nucleus is replaced by a 

 large number of secondary ones, which are apparently re- 

 lated to the elaboration of food material for the growing 

 embryo, when it gains access to the cavity of the sac. 



" But if this be so, if pollination be unnecessary, why 

 should the access of insects be essential to the develop- 

 ment of embryos ? The phenomena presenting them- 

 selves in connection with the male flowers of gall- 

 receptacles appear to aff'ord a clue to answering this 

 question. It is just as impossible for the male flowers to 

 come to perfection — ^just as impossible for perfect pollen- 

 grains to be developed without the access of insects to the 

 gall-receptacles — as it is for embryos to be developed in 

 female ones under parallel circumstances. 



" The development of embryos in F. Roxburghti, then, 

 appears normally to be an asexual process dependent on 

 hypertrophic budding of a specialized portion of the 

 nucellar parenchyma, and it appears not improbable that 

 the phenomenon is not peculiar to the species, but is the 

 rule in the case of other figs also. This, of course, 

 requires further investigation ; but in the only instance in 

 which I have yet had time to examine the matter — in 

 the case of F. hispida — there can be no doubt that it 

 is so." 



From the foregoing extracts it will be seen that Dr. 

 Cunningham insists on two extraordinary phenomena — 

 namely, the impossibility of the formation of pollen in the 

 absence of insects, and the formation of embryos by bud- 

 ding outside of the embryo-sac instead of sexual develop- 

 ment. As to the first, improbable as it may seem, I am 

 assured by two or three independent observers, who have 

 had opportunities of testing Dr. Cunningham's work, that 

 they have arrived at the same conclusions. As to the second, 

 the asexual formation of embryos is not so very rare an 

 occurrence, according to Strasburger in his elucidation of 

 polyembryony and the so-called parthenogenesis. Then 

 as to the whole, the phenomena would seem to point to 

 the extinction of sexuality. The points are that the 

 development of both pollen and embryo is due to a 

 NO. 1094, VOL. 42] 



stimulation of the tissues caused by the punctures of 

 insects. Therefore Dr. Cunningham might with more 

 propriety have entitled his paper " The Phenomena of 

 Non-Fertilization." W. BOTTING Hemsley. 



SYNONYMY OF THE POLYZOA. 

 A Synonymic Catalogue of the Recent Marine Bryozoa. 

 By E. C. Jelly, F.R.M.S. (London: Dulau and Co., 

 1889. 



THIS is a work for which all students of the Polyzoa 

 (Bryozoa) should be grateful. It supplies an un- 

 doubted want, and will greatly facilitate the investigation 

 of the large and interesting class with which it deals. 



Synonymy is certainly not an attractive element of 

 natural history study. Indeed, anything of less intrinsic 

 interest cannot well be imagined, and yet it has a specific 

 value in relation both to morphological and systematic 

 work, and it is of the first importance that it should be 

 carefully determined. A just and accurate synonymy is 

 of course an essential condition of a sound nomenclature ; 

 it is a key to the actual state of knowledge, and an index 

 to the sources in which it must be sought, which is 

 invaluable to the student. It is also a safeguard against 

 duplicate and delusive names. 



Miss Jelly's " Synonymic Catalogue of the Recent 

 Marine Bryozoa " fills a vacant place. There is not, so far 

 as we know, any work which occupies the same ground. 

 "It aims," as the author explains in her preface, " at 

 bringing into view all the names of published recent 

 Bryozoa, with as full a synonymy as may be possible." 



The fossil forms belonging to recent species, and these 

 only, are included in the synonymy. The work, which 

 bears the marks of careful and conscientious labour, 

 brings before the student within small compass the entire 

 series of published Polyzoan forms belonging to the 

 recent fauna ; supplies him with a reference to the book 

 in which each species was first described and with the 

 name of the writer who first described it ; tracks it, as it 

 were, however disguised by variety of name, from author 

 to author, and so in fact furnishes an index to the whole 

 range of the systematic literature. 



The value of such a guide to the student of the Polyzoa 

 must be at once evident. It economizes his labour; it 

 enables him to enter upon original investigation with a 

 full knowledge of what has been already done, and it saves 

 him from adding to the weariness and perplexity of those 

 who may follow him by multiplying duplicate names. 



Within the last few years large additions have been 

 made to the known species of Polyzoa, the diagnosis of 

 which is distributed to a great extent through the bio- 

 logical journals of Europe and America. With all the 

 care that he can exercise the student is continually liable 

 to overlook some paper in some obscure periodical of 

 which perhaps he has never heard, and, as a result, to add 

 another name to the already burthensome synonymy. In 

 point of fact, as a matter of convenience the synonymy of 

 each class of any extent is worthy of separate and special 

 treatment ; and such a wofk as Miss Jelly has now 

 supplied should be regarded as an essential part of the 

 apparatus of the student who devotes himself to descrip- 

 tive and systematic work. 



We cannot but regret that Miss Jelly has abandoned 



