152 



SCIENCE. 



[N. S. Vol. XXIII. No. 578. 



Because of the importance that regenerative 

 phenomena have in the consideration of cer- 

 tain fundamental biologic problems, one might 

 be tempted to try to find some significance 

 in whatever special examples of regeneration 

 happen to come under one's own observation. 

 The relation between physiological regenera- 

 tion and restorative regeneration is a subject 

 ■ very near at hand, if one were to look for 

 something to speculate about in connection 

 with what I have noted in this paper on re- 

 generation in insects. But with Morgan, it 

 seems to me that ' we do not gain any insight 

 into either of the processes, so far as I can 

 see, by deriving one from the other, for the 

 process of restorative regeneration may be in 

 point of time as old as that of physiological 

 regeneration.' Indeed, among the insects we 

 have good grounds for believing restorative 

 regeneration older than the particular proc- 

 esses of physiological regeneration which 

 regularly accompany the post-embryonic devel- 

 opment of insects with complete metamor- 

 phosis. For these insects are admittedly the 

 recent, the post-Tertiary, ones, while the Or- 

 thoptera, among which, especially, restorative 

 regeneration is widespread and unusually well 

 developed, are among the oldest of living in- 

 sect orders. They make up the bulk of insects 

 known from pre-Tertiary times. The most 

 extensive and radical of physiological regen- 

 eration processes occur precisely among the 

 most specialized, the most recent, insects. 



Finally, as concerns the large question of 

 whether regeneration is to be looked on as a 

 certain primary, primitive, attribute of organ- 

 isms whose manifestation becomes weaker as 

 complexity in structure and function is at- 

 tained (in course of descent), or whether, as 

 is held by the Neo-Darwinians, it is to be 

 looked on as an adaptation which has been 

 transmitted through a long and many-branched 

 course of descent, gradually weakening during 

 this transmission until in the more complex 

 organisms it is largely lost, although, in con- 

 sonance with need, often retained even among 



acters of Reproduced Appendages in Arthropoda, 

 Particularly in the Blattidae,' Proc. Zool. Soc. Lon- 

 don, 1898, pp. 924-928 ; and Tornier, Zool. Anzeig., 

 Vol. 24, 1901, pp. 634-604. 



higher forms, this is a question I shall refer 

 to only in so far as to say that the evidence 

 presented by all that we know of regeneration 

 in insects, taken together, certainly does not 

 warrant any such definite conclusion as 

 Tornier expresses on ' the basis of his experi- 

 ments with certain dragon-fly and May-fly 

 larvae, viz., that regeneration in insects is an 

 adaptation produced by natural selection. 

 Vernon L. Kellogg. 

 Stantokd Univebsitt, Cal. 



a preliminary note on ascus and spore 

 formation in the laboulbeniace^. 



Concerning the systematic position of the 

 Laboulbeniacese many opinions have been ex- 

 pressed. DeBary (1884) included them in 

 his doubtful Ascomycetes; Thaxter (1895), of 

 all best qualified to speak, referred them to 

 the Ascomycetes; Karsten (1895) maintained 

 that they were not Ascomycetes at all," but 

 that they occupied a position intermediate be- 

 tween the smuts and the Pyrenomycetinese, 

 while Engler (' Syllabus der Pflanzenfamilien,' 

 1903) has elevated them to the rank of a class 

 quite removed from both the smuts and the 

 Ascomycetes. These differences in opinion 

 have arisen from a lack of knowledge of the 

 actual phenomena of spore production, a gap 

 due to difficulties in obtaining and manipu- 

 lating material suitable for cytological in- 

 vestigation. 



In the course of recent investigations on the 

 Ascomycetes I have given some attention to 

 these peculiar and interesting forms, and an 

 examination of microtome sections of well- 

 preserved perithecia has revealed features that 

 are apparently of undoubted significance in 

 their bearing on the problem of the phylo- 

 genetic position of this group. 



As for the spore sac, it has been discovered 

 that each is primarily occupied by a fusion 

 nucleus. Three successive nuclear divisions 

 follow. The spore initials are delimited from 

 an abundant epiplasm under the superintend- 

 ence of the last generation of nuclei. The 

 young spores are bounded by a plasma mem- 

 brane, and the cavities in the epiplasm in 

 which they lie are lined by a membrane of 

 similar character. Indeed, the phenomena of 



