164 



SCIENCE. 



[N. S. Vol. VII. No. 162. 



type of unilocular sporangium. It is there- 

 fore impracticable to connect Cycas with 

 Isoetes, on account of the sporangial struc- 

 ture, and either an independent develop- 

 ment of heterospory must be assumed for 

 the Cycadaceie or they must be connected 

 with the Coniferoe and traced back to Selag- 

 inella. That is, the evidence on the whole 

 points to an independent deve opment in 

 Cycadacese, and also probably in Gingko- 

 acefe, of multiciliate spermatozoids. This 

 conclusion is borne out by the marked pecu- 

 liarities of Cycad and Giugko spermatozoids 

 as described by Ikeno, Hirase and Webber, 

 although important resemblances between 

 the development of the spermatozoid in 

 Zamia, as described by Webber, and in 

 Equisetum, as described by BelajefF, must 

 be conceded. 



The researches most needed at present are 

 upon the genesis of the sperm-nucleus 

 in Coniferfe and Gnetales to discover 

 whether bodies which might be regarded as 

 reduced blepharoplasts are present, and if 

 so whether thej'- indicate a multiciliate or 

 biciliate spermatozoid in primitive Tax- 

 acese. 



In general, it may be said that the poly- 

 phyletic theory of the origin of the gym- 

 nosperms is strengthened by the new re- 

 searches, but it I'emains more difficult than 

 before to include Isoetes-like forms among 

 the probable ancestors of seed- plants. In 

 addition, the very considerable differences 

 between gymnospermous and angiosperm- 

 ous seeds arising from the wide variance in 

 endosperm formation, together with the 

 singular inversion (?) of the female plant in 

 VanTieghem's Basigamese and the suppres- 

 sion of the ovule in his Inovulese and of the 

 nucellus in the Innucellefe, together justify 

 the view that the Spermatophyta is not a 

 homogeneous group, but is purely ecolog- 

 ical, comprising groups of widely different 

 phylogeny, but, in general, similar adapta- 

 tions arising under what I have previously 



termed symbiotic alternation of genera- 

 tions. 



Conway MacMillan. 



PALEONTOLOGICAL NOTES. 

 Among the recent papers of Mr. A. Smith 

 Woodward, of the British Museum, are 

 several matters of general interest in pale- 

 ontology. Referring to Professor Marsh's 

 discussion at Ipswich of the ' Jurassic Age 

 of the Wealden Vertebrate Fauna,' Mr. 

 Woodward has listed the Wealden fishes 

 very carefully, and concludes as follows :* 



" The result is, therefore, that all the known Eng- 

 glish Wealden fishes are survivors of typically Jurassic 

 genera, except Neorhombolepis and Cwlodus, and 

 these are their little-modified representatives. None 

 but Beloiiostomus appear to range throughout the 

 Cretaceous. In fact, the Wealden estuary seems to 

 have been the last refuge of the Jurassic marine fish 

 fauna in this part of the world, not invaded even by 

 stragglers from the dominant race of higher fishes 

 which characterized all the seas of the Cretaceous 

 period. The Wealden river drained a land where a 

 typically Jurassic flora flourished ; the only two 

 known JIammalian teeth from the Wealden resemble 

 those of a Purbeckian genus, and now it is clear that 

 the fishes agree both with these and the reptiles in 

 their alliance with the life of the Jurassic era." 



The second note relates to the occurrence 

 of a gigantic Pterodactyl in the Cretaceous 

 of Bahia, Brazil, and concludes with the 

 following note :t 



"Not being able to determine the genus of the 

 Brazilian Cretaceous Pterodactyl, it is equally impos- 

 sible to estimate the size of the skull or the animal 

 itself from a single bone. There is too much varia- 

 tion from the proportions of the snout and the relative 

 dimensions of the head among Pterodactyls to admit 

 of any such induction. To judge by Marsh's figure 

 of the skull of Pleranodon, however, the Brazilian 

 form iiust have even exceeded in size the gigantic 

 species of this North American genus, of which the 

 head sometimes attains a length of four feet." 



* ' On the Affinities of the English Wealden Fish- 

 Fauna.' Ocol. Mag., Vol. III., No. 380, p. 69. 



t ' On the Quadrate Bone of a Gigantic Ptero- 

 dactyl,' etc. Annals and. Blagazine of Natural History, 

 Ser. 6, Vol. XVII., 1896. 



