238 SUMMARY OP CURRENT RESEARCHES RELATING TO 



Structure of Pylomata of Protista.* — ^Herr F. Dreyer gives us a 

 comparative and developmental history of the structure of the pylomata 

 of the Radiolarians and of the Protista in general, to which he adds a 

 system and description of new and known pylomatic Spumellaria. The 

 ■work is mainly based on ' Challenger ' material, and may be considered 

 as a continuation of that done by Haeckel on the Eadiolaria. The 

 term " pylom " is used instead of " osculum," which was the name used 

 by Haeckel for the oral orifice of some Spumellaria; the change of 

 designation recommends itself as preventing any misunderstanding 

 which might arise from the central capsule having an " osculum." 



In the chapter on the system and special description of the pylomatic 

 Spumellaria a number of new forms are described, which we must be 

 content to enumerate. The Sphseropylida is a new family of the 

 Sphseroidea ; it has two subfamilies, the Monostomida, with the genus 

 Sphseropyle, in which there are seven new species, and Prunopyle, in 

 which there are eleven ; and the Amphistomida has a single new genus 

 Stomatosphsera, with two species. Of the Phacodiscida, the Phacopylida, 

 with PJiacopyle stomatopora g. et sp. n., is a new family; of the 

 Porodiscida there are eight new species; the Spongopylida is a new 

 family of the Spongodiscida, with a single genus Spongopyle and eight 

 species. The Larcopylida is a new family of the Larcoidea for Larco- 

 pyle Butschlii g. et sp. n. 



The third chapter deals with the comparative anatomy and develop- 

 ment of the pylomata of Radiolarians in general. These structures may 

 be primary or secondary ; the former are pylomata which were already 

 present when a connected skeleton began to be formed, the latter have 

 appeared after the skeleton was complete, and, in many cases, when it 

 was already highly developed. The characters of these are considered 

 in detail. 



The influence of the pyloma on the form of the whole shell in the 

 Protista in general is next discussed ; it appears to have a tendency to 

 draw out the shell in the direction of its primary axis. In this direction 

 the radial skeletal parts become disposed. The various modifications 

 which obtain are dealt with in considerable detail. 



The fifth chapter treats of the constancy of the pylom in species and 

 its ontogenetic development in the Eadiolaria. It would appear that the 

 pylom is not constant, being sometimes present and sometimes absent, 

 whence we may conclude that the process of pylom formation is still in 

 a fluid condition. It does not, of course, follow that all pylomata are 

 inconstant, and in many cases it is not so. 



The author gives ample evidence of the extraordinary " labyrinth of 

 forms " which is to be seen among Ehizopods, and hopes that this and 

 succeeding memoirs will do something to make us understand the 

 complex morphological relations of the Ehizopoda and the causes that 

 have brought them about. 



* Jenaische Zeitschr. f. Naturwiss., xxiii. (1888) pp. 77-214 (6 pis.). 



