FREE MESSMATES. 43 



ing to Grube, in the tubes or galleries of the Teredines. 

 These dangerous acolytes introduce themselves furtively 

 into the retreat of their host ; and, always on the watch, 

 they obtain at all times, and in every place, a certain 

 prey, and a hiding-place from which they can take then- 

 share of their neighbour's goods. Another nereis, ob- 

 served by Delle Chiaie, Nereis tethycola, lives in the 

 cavities of a sponge, the Tethya jpyrifera, which is visited 

 by so many messmates and parasites, that it becomes a 

 kind of hotel, where every one establishes himself at his 

 ease. Risso also mentions a Lysidice erythrocej^hala 

 which lives in sponges. 



In the same class is found an Amphinoma, a beauti- 

 ful red-blooded worm, which proudly w^ears a plume of 

 red branchiae on its head, and which Fritz Miiller ob- 

 served on the coast of Brazil, begging assistance from a 

 poor Lejms anatifera. Many Polynoes live upon other 

 annelids ; the Harmothoe- Malmgreni on the sheath of 

 the Choetopterus insignisy the Ant'moe nohilis on the case 

 of the Terehella nehulosa. Prof. Eay Lankester has 

 lately communicated some observations on this subject 

 to the Linnaean Society of London, and Dr. M'Intosh 

 mentions some new species leading the same kind of life 

 on the coast of Scotland. 



Grube found at Trieste, in a star-fish {Astropecten 

 aurantiacus), between its rows of suckers, a Polyno'e 

 malleataj with its stomach attached to the animal ; and 

 Delle Chiaie has lately observed on an asteria, a Nereis 

 squamosa by the side of a Nereis flcxuosa. Mons. Grube 

 thinks that the nereis of Delle Chiaie is no other than 

 the Polyno'e malleata. Lobsters are often covered with 

 very small tubicular worms, which invade the wholo 



