Po] MEDUSA FROM THE GULF STREAM. 521 
DISCOIDEA. 
Family VELELLIDZ. 
VELELLA MUTICA, Bosc. 

Catalogue 
nuaniner Station. | North latitude. | West longitude. 


2) / ut ° / u 
11644 | Hyd. 753 40 18 30 53 39 30 
15748 2727 36 35 00 74 03 30 
15749 2723 36 47 00 73 09 30 
15751 2727 36 35 600 74 03 30 
15755 2725 36 34 00 73 48 v0 



Family PORPITID. 
PORPITA LINNZANA. 

Catalogue | 
number. | 
| 
Station. | North latitude. | West longitude. 





11640 | 2536 | 39 56 15 70 47 30 
11641 | 2537 | 39 56 45 10" (5ORt30 
11642 | 2538 | 39 57 ‘30 MON eee 
11643 | 2566 | 37 23 00 18 08 00 
CRASPEDOTA. 
Family AAQUORIDZ, Eschscholtz. 
Portycanna, Heeckel. P 
It is very difficult to distinguish the genera and species of the above 
family, especially the American representatives. 
A. Agassiz describes three species of Zygodactyla from our coast: 
Z. grenlandica Ag., Z. crassa A. Ag., and Z. cyanea, A. Ag. Heckel 
places Z. grenlandica, Z. crassa, and Cremastoma flava, A. Ag., in the 
genus Polycanna, Heckel, while Z. cyanea A. Ag. is referred to his genus 
Mesonema as M. cyaneum. According to A. Agassiz, the tentacles in 
Z. grenlandica, Z. crassa, and C. flava are more numerous than the 
chymiferous tubes. This is true also, according to Heckel, of P. vitrina, 
Heck. In P. germanica and P. italica, Heeck., the tubes and tentacles 
correspond in number, while in P. fungina, Heeck., the radial tubes are 
more numerous than the tentacles. These characters form the three 
subgenera: ‘ 
1. Rhacostoma. Radial tubes more numerous than tentacles. 
2. Cremastoma. Radial tubes equal in number to the tentacles. 
