ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 'I'M 



coarse network ; the nucleus fragments and the fragments spread. The 

 spermospores matured in the canals migrate to basal endoderm of dacty- 

 lozooids, lose their walls, pass as colonies of young spermoblasts into 

 cavity of zooid, push out the wall into sporosacs and rest there till 

 mature. Occasionally they were found in gastrozooids. 



The ectodermic origin of sex-cells (Hertwigs and Weismann) is con- 

 firmed. The absence of segmentation and sperm morula may be associ- 

 ated with migration after commencement of development. There is no 

 corroboration of the suggestion that the Millepora have lost their yolk. 

 The Hydrocorallina3 are probably a separate stock, never with medusi- 

 form gonophores, and without any relation to Hydractinia. 



Structure and Affinities of Parkeria.* — Prof. H. A. Nicholson 

 thinks that Mr. H. J. Carter was right in referring the genus Parkeria 

 to the Hydrozoa. All the known facts as to the chemical constitution, 

 mode of growth, and general structure of the coenosteum, no less than 

 ,the minute structure of the skeleton-fibre, seem to him to point in this 

 direction. The genus may be regarded as intermediate between the 

 Hydrocorallines and the Hydractiniidai ; it resembles the former more 

 closely in the minute structure of the skeletal tissue, and the latter in the 

 mode of growth by the production of successive concentric lamellas 

 separated by rows of chamberlets. With regard to its supposed allies 

 among fossil forms, the author states that Syringosplteera differs in not 

 increasing by the formation of successive concentric lamellae with inter- 

 vening rows of chamberlets, and that that genus is a true Hydrocoralline ; 

 Porosphsera is probably a Lithistid sponge ; the resemblances between 

 Parkeria and Loftusia are merely superficial ; there are unquestionable 

 points of resemblance and marked points of difference between Parkeria 

 and the groups of Stromatoporoids. 



Growth of Flabellum.t — Dr. E. von Marenzeller finds that in the 

 genus Flabellum the new septa arise between the older ones, as in other 

 stony corals. In some species this is effected regularly, but in others 

 the chambers at the end of the long axis are specially numerous ; and in 

 them septa of higher orders appear before those of the next lower order 

 have been developed in other chambers. In a few species the septa 

 retain their relative sizes, but in most those of the second and third 

 order grow as large as those of the first ; this happens particularly in 

 those species in which the development of the septa of the higher orders 

 is irregular. The equalized septa ordinarily have between them three 

 septa, two of the last and one of the penultimate order, and they thus 

 give rise to that division into polyparies, which is so characteristic of 

 the genus. In addition to notes on known forms, there is a description 

 of F. coalitum sp. n. from Japan. 



Classification of Alcyonaria.J — Prof. T. Studer, who has, in con- 

 junction with Prof. E. P. Wright, studied the Alcyonacea of the 

 ' Challenger ' Expedition, has an essay on the classification of the order. 

 This is a matter of some difficulty as the palaeontological history can 

 never be completely known, owing to the fact that we can never know 

 the structure of the polyps. In all Alcyonaria, with the exception of 

 the small family Haimeidae, which perhaps represent the primitive form, 



* Ann. and Mag. Nat. Hist., i. (18S8) pp. 1-12 (1 pi.), 



t Zool. Jahrb., iii, (18S7) pp. 25-50. 



X Arch. f. Natnrgesch., liii. (1887) pp. 1-74 (I pi.). 

 1888. s 



