Mr. C. Spcnce Bate on the Nidijication of Ci-ustacea. 163 



be easily made to leave it, and will make another if it be de- 

 stroyed. On tlie other hand, some of the other individuals in 

 the same jar will make no tubes ; and often, at low water, they 

 may be seen swimming about, perfectly free. The same is true 

 of some of the other species of the family here mentioned, and 

 of many species whose habits I had o])portunities of observing 

 in the harbour of Charleston, S.C., in the winter of 1851-5;i.^' 



Kroyer, in his great work on ' Scandinavia,^ &c., figures a 

 previously undescribed Crustacean of the same order under the 

 name of Siphonocetus typicus (PI. VIII. tig. 1), which he found to 

 inhabit small cases (not unlike those made by the Caddis-worm), 

 built of small pebbles, sand, &c. Beyond these facts, I am not 

 aware of any observations being published upon this curious 

 subject. 



Some years since, before I gave much attention to the sub- 

 ject, I had in a glass case a few Amphipoda in sea-w-ater, with a 

 little weed. After a short time, an hour or two, I was surprised 

 to find that one of these small creatures had managed to bend 

 round a portion of a leaf of green Ulva upon itself, and cement 

 the same into a tube-like case, in which it lived, putting out its 

 head and antennse only ; uj)on being disturbed at one extremity, 

 it would quickly turn within its abode, and protrude its head at the 

 other. I thought it curious at the time, but pursued it no far- 

 ther, until more recent and longer-extended opportunities showed 

 me that these were by no means isolated instances among Crus- 

 tacea, but that a large and well-marked group enjoy this power; 

 and that this group is again capable of being divided, — one divi- 

 sion being distinguished by the construction of tubes open 

 (occasionally ?) at each end, the other by cases bearing a closer 

 resemblance to nests, irregular in form, short, and open only at 

 one extremity. 



The animals which construct these two kinds of abodes possess 

 an external structure that distinctly separates them from one 

 another, and both again are distinguishable from the burrowers, 

 or those which dwell in abodes that they have made by exca- 

 vating channels in clay, mud, or wood. 



Together these three groups form the family Domicola among 

 the Amphipods, but separately they represent distinct sub- 

 families, the value of which rests upon the structure of the ani- 

 mal composing each. 



It is upon a clear appreciation of this structure that the genus 

 Amphito'e has been removed from the position that has gene- 

 rally been assigned to it by authors, viz. near to Gammarus, 

 and placed among the Podocerides. 



When engaged in making observations for the "Report on the 

 British Amphipoda" for the British Association, I kept in a glass 



11* 



