PALTNURUS OR THE SPINY LOBSTER OF BOMBAY. 361 



and form a clear mental picture o otherwise dull and un- 

 interesting facts. 



I am well aware that the object of most of our University students 

 is simply to pass their examination and that as speedily as possible, 

 but they as well as the honoured few who love science for its own 

 sake, will find they can master well the syllabus of Biology by prac- 

 tical study and dissection in at least one-fourth the time mere reading 

 may enable them to scrape through by the charity of an indulgent 

 examiner. 



Therefore. 1 say, first catch your Palinurus. This you can do with 

 impunity as he possesses none of the powerful forceps with which his 

 European cousin, the Lobster, or some of the Indian Prawns can 

 pinch and wound the unwary investigator. 



If alive he will probably make a croaking noise as you lift him. 

 This sound as you can verify yourself is caused by rubbing the first 

 movable joint of the large feelers against the neighbouring fixed part. 



He may perhaps startle you by forcibly flapping his tail against the 

 under surface of his thorax. When in his native haunt, the sea, he is 

 able to suddenly dart backwards by similar powerful strokes of the 

 tail, but the usual mode of progression is swimming by gentle strokes 

 of the flat tail fin, while the swimming feet all row together with an 

 even swing like the oars of a boat. When on the bottom of the sea 

 he half swims, half walks, on the long thoracic legs. 



Note the movement of the jaw apparatus. Each jaw moves hori- 

 zontally to and from the middle line of the body ; not up and down 

 as do the jaws of a dog or man. 



Next look under the anterior edge of the large shield-like covering 

 of the cephalo-thorax. You will notice a small scoop or paddle-shaped 

 appendage moving rapidly to and fro two or three times a second. 

 This is the paddle or scaplmynathite (Gr. svaphe, boat, gnathos, jaw), 

 by means of which the water entering the gill-chamber from behind 

 is scooped out in front so that a continuous current keeps bathing the 

 gills to enable them to absorb the oxygen dissolved in the water and 

 get rid of the carbonic acid. 



The course of the current is easily demonstrated by returning the 

 animal to the water after it has been in the air for some time. On 

 re-immersion, bubbles of air are for some time seen to come out from 

 under the anterior edge of the gill-cover. Should this not satisfy 



