TELEOLOGY AND MORPHOLOGY. 139 



A house is certainly, to a great extent, an illustration 

 of adaptation to purpose, and its structure is, to that 

 extent, explicable by teleological reasonings. The roof 

 and the walls are intended to keep out the weather; the 

 foundation is meant to afford support and to exclude 

 damp; one room is contrived for the purpose of a 

 kitchen; another for that of a coal-cellar; a third for 

 that of a dining-room ; others are constructed to serve as 

 sleeping rooms, and so on ; doors, chimneys, windows, 

 drains, are all more or less elaborate contrivances directed 

 towards one end, the comfort and health of the dwellers 

 in the house. What is sometimes called sanitary architec- 

 ture, now-a-days, is based upon considerations of house 

 teleology. But though all houses are, to begin with and 

 essentially, means adapted to the ends of shelter and 

 comfort, they may be, and too often are, dealt with from 

 a point of view, in which adaptation to purpose is largely 

 disregarded, and the chief attention of the architect is 

 given to the form of the house. A house may be built in 

 the Gothic, the Italian, or the Queen Anne style ; and a 

 house in any one of these styles of architecture may be 

 just as convenient or inconvenient, just as well or as ill 

 adapted to the wants of the resident therein, as any of 

 the others. Yet the three are exceedingly different. 



To apply all this to the crayfish. It is, in a sense, 

 a house with a great variety of rooms and offices, in 

 which the work of the indwelling life in feeding, breath- 

 ing, moving, and reproducing itself, is done. But the 



