ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 455 



others having only their genera indicated. In concluding the de- 

 scription of the thirteenth, which appears to be a representative of a 

 new form, Dr. Erdmann remarks that the developmental process of 

 the septa of Actinige may be divided into two periods ; the first ends 

 when the first six or primary pairs of septa have been developed ; in 

 the second period the septa of the second, third, and other orders are 

 laid down ; in the Zoanthea3 the law of development in the second 

 period is different, owing to the fact that only two processes can give 

 rise to new pairs of septa. It seems to be clear that in them the 

 number of septa is in direct relation to the size of the animal, which, 

 as a general rule, corresponds to its age. 



The author gives definitions of all the genera, and woodcuts illus- 

 trating the arrangement of the septa. 



North Atlantic Pennatulida*— Drs. D. C. Danielssen and J. Keren 

 have produced another of their beautifully illustrated memoirs on the 

 animals collected by the Norwegian North Sea Expedition ; the most 

 interesting part of this memoir deals with Umhellula encrinus, the 

 specific name of which we owe to Linnasus, though our knowledge of 

 the species has been as yet so slight. Twelve specimens, forming a 

 very complete series of stages and sizes, were obtained, the largest of 

 which is, to judge from the illustrations, a magnificent example. The 

 polyps of this species appear to be viviparous. 



Eleven of the thirteen species found are new, and of the eight 

 genera represented, two are new ; these are called Svava and Gim- 

 neria ; the former is small, has rudimentary fins, and is without 

 spicules in the sarcosorae, cells, or polyps ; the gonads are developed on 

 the lateral zooids, while the fully developed polyps are barren ; the 

 larvae are set fi-ee by the mouth, as in Corallium. Only a fragment 

 attests the generic characters of Gunneria, but the generic characters 

 may be seen in the large number of spicules on the bodies of the 

 polyps, tentacles, and sarcosoma, so that the new genus appears to 

 approach the Gorgonidae. 



Porifera. 



Relationship between Sponges and Choanoflagellata.f — Prof. F. 

 E. Schulze has criticized in detail the theory, lately revived by Saville 

 Kent, that the sponges were flagellate colonies. Allowing, of course, 

 the suggestive resemblance of the collared cells of sponges with the 

 collared flagellates described by Saville Kent as Choanoflagellata, 

 and by Biitschli as Calico-mastiges, Prof. Schulze points out that 

 the similarity does not amount to identity, and even if it did, would 

 not necessitate the conclusion that sponges were colonies of Flagellata. 

 In regard to Saville Kent's description of numerous sponge larvae, 

 according to which the swarm-gemmules consist of ciliated individuals 

 which soon all acquire collars, the absence of corroboratory re- 

 searches, and the opinion of all other investigators are noted, while 



* Den Noiske Nordhavs-Expedition. Zoologie— Penuatulida, 84 pp. and 

 12 pis., fol., 1884. 



t SB. K. Preusa. Akad. Wiss., 1885, pp. 179-91. 



