662 MR. A. "Vr. WATEES ON MEMBEANIPOBID^. 



Ill most o£ these temporary groups many species are doubt- 

 fully placed, but there are some characters in common, and in 

 this way we can gradually become better acquainted with the 

 relationships. On the other hand, as we cannot definitely fix 

 the groups, it seems better not to give new generic names. 



The areolated spaces which are found in M. acuta, H., M. cra- 

 ticula, Alder, M. circmnclathrata, H., M. sejuncta, MacGr., as 

 well as in Gliorizopora, do not seem to furnish a character upon 

 which a group can be formed. 



After removing from Memhranipora the two species rohorata 

 to Flahellaris , and serrata to Flustra, I have tried to group the 

 Membraniporidse with the aid of all the characters available, 

 including the rosette-plates and the form of the ovicells. 

 Greueric division is at present somewhat risky, and the groups 

 now given should be cheeked by a study of the larva, an 

 examination of the interteutacular organ, the anatomy of the 

 polypide, and special attention should be given to the primary 

 zooecia. My material has not enabled me to make a comparative 

 study of this last point, and a recent visit to the Zoological 

 Station at Yillefranche, where I hoped to make preparations from 

 well-preserved recent material, was disappointing, as there seems 

 to be very few Memhraniporce in the Bay. 



There are 12 tentacles in M. pilosa, L.; 20 in M. memhranacea, 

 L. ; 15 in M. rohorata, H. ; 23 in M. falcifera, B. ; about 16 in 

 Chaperia cervicornis, B. ; 14 in Onychocella angulosa, Eeuss ; 14 

 in M. jiustroides, H. ; 14-16 in Memhraniporella nitida, Johnst. 

 ifideB..). 



Through the kindness of Mr. Kirkpatrick I have been able 

 again to look through the mounted Memhraniporce of the 

 ' Challenger' collections, and have been able to make corrections 

 in ' Challenger ' M. lineata, M. umhonata, M. curvirostris var., 

 M. crassiviarginata, M. incrustans, M. perfragilis. 



I have again carefully examined my Mediterranean specimens 

 for the purpose of revision, and Miss Jelly has sent me several 

 from South Africa and other localities ; and Mr. J. Yates 

 Johnson has submitted a few from Madeira. 



