ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 1009 



Structure and Function of the Sphaeridia of the Echinoidea.* — 



Mr. H. Ayers supplements the observations of Loven by a large 

 number of structural facts, which, besides allowing of greater accuracy 

 in determining the function of these peculiar organs, furnish an ex- 

 ample of a highly specialized organ in this group that is comparable 

 to the otolith sacs of Synapta. 



Japanese Echinoidea.j — Dr. L. Doderlein enumerates and gives 

 an account of the forty-seven sjiecies collected in the Jajianese seas, 

 an extraordinarily large proportion of which are described as new ; 

 some of these will no doubt be found to be varieties of some of the 

 very variable members of this class. 



Brisingidae of the 'Talisman' Expedition. J — Prof. E. Perrier 

 finds that the new forms of Brisingidae collected by the ' Talisman ' 

 fill up some of the lacunae which separated this group from the rest 

 of the Asteroidea ; a new genus Freyella contains a species F. 

 sexradiata, which leads directly to Pedicellasler, with its five or six 

 arms ; Coronella recalls exactly the a2)pearance of Asterias ienuispina 

 and its allies, and has, like them, a reticulated dorsal skeleton ; the 

 ambulacral tubes are, however, disposed in two rows. In the de- 

 velopment of the dorsal skeleton we have the following ascending 

 series : — Hi/menodiscus Agassizii, Brisinga mediterranea, B. elegans, 

 B. endecacnenws, B. coronata, B. semicoronata, B. robusta, Labidiaster 

 radiosus, Brisingaster robillardi, Pedicellasler typicus, Coronaster 

 Parfaitiy and Asterias tenuispina. The Freyellse form an aberrant 

 series. 



Asteroidea of Mauritius.§ — M. P. de Loriol has published the 

 second part of his ' Catalogue Raisonne ' of the Echinoderms of 

 Mauritius, in which old as well as new species are described and 

 figured. 



Coelenterata. 



Development of Agalma.||— Mr. J. W. Fewkes states tbat, in 

 the course of its development, the egg of Agalma passes through 

 three very distinct stages : the primitive larva, the Athorybia-stage, 

 and the larva like the adult but still retaining certain provisional 

 structures. The first stage is alone here considered, and it is regarded 

 by the author as giving us the key to the phylogeny of the Oceanic 

 Hydrozoa. The observations on impregnation and cleavage arc de- 

 scribed in detail ; towards the end of the segmentation period extra- 

 ordinary protoplasmic elevations are to be observed from the surface 

 of the egg. 



AVheu the development of the primitive or larval liydrophyllium 

 is at its maximum the yolk of tlie egg is still spherical and little 

 reduced ; the egg is almost completely invested by the helmet-shaped 



♦ Science, vi. (1885) p. 226. Since published in Quart. Journ. Micr. Sci., 

 xxvi. (\HHr,) pp. aO-.O'i (1 iA.)post. 



t Arr:li. f. Nuturgesch., li. (1885) pp. 73-112. 



t Cornptf.H U< ndiis, ci. (1885) pp. 441-4. 



§ Mem. Soc. Pliy.s. et d'Hitt. Nat. Geneve, xxix. (1885) 83 pp. (IG pis.). 



II bull. Mus. Corap. Zool. Camb., xi. (1885) pp. 2:{9-75 (4 pis.). 



