360 TEE ZOOLOGIST. 



on April 1st, I noticed a good instance of the utility of the vibratile 

 fin of the Five-bearded Eockling {Motella mustela) in keeping clear the 

 dorsal groove. The fishes had been in the collecting-can for a day 

 01" two, and the water was so dense with rust that the fishes could 

 not be seen until they were lifted out. The slimy body of the Eock- 

 ling, which was about 6 in. in length, was completely covered with a 

 thick coat of rusty particles, the vibratile fin and the groove excepted, 

 and the latter stood out conspicuously as a smooth dark area from 

 the red rust. Eocklings coated with sand, but with a clear groove 

 are of course sometimes to be found ; but that the fin should act so 

 efficiently during a long and exhausting journey in a collecting- can 

 of rusty water seems noteworthy. I may add that vibration of the 

 fin could be st&,rted by a touch of the finger on the side of the fish, 

 close to the fin, whilst the otherwise quiescent animal was held in 

 the open hand for examination. The vibration was started in this 

 way several successive times, but the movements only lasted for 

 fifteen or twenty seconds on each occasion. — H. N. Milligan. 



ASTEEOIDEA. 



A Starfish feeding on a Spider-Crab. — A Common Starfish 

 {Asterias ruhens), of about 4 in. in diameter, was placed in an 

 aquarium on November 29th last. The aquarium already contained 

 several Edible Mussels and Purple-tipped Sea-Urchins, and also two 

 large male individuals of the Long-legged Spider-Crab {Stenorhynchus 

 phalangium). The Starfish was fed with pieces of mussel and beef. 

 On the morning of December 4th the Starfish was found to be feeding 

 on one of the Spider-Crabs, which was dead. It is impossible to say 

 whether or not the Starfish had seized the Spider-Crab before death ; 

 but it may be mentioned that the crustacean seemed healthy on the 

 previous night, and in the light of what we know of the voracity and 

 aggressiveness of this echinoderm it may be thought not improbable 

 that the Starfish had attacked and killed the Spider-Crab, — H. N. 

 Milligan. 



