94 L. A. BORRADAILE. 



its shell, (viii) An individual, seemingly dead, may often be revived by being placed in 

 the air, just as a marine crab, dying from exposure to the air, will come to life in water'. 



Some 200 specimens, mostly of the species C rugosus and C. perlatus, were experi- 

 mented with. The fresh water used was rain gathered in a " galvanised " iron tank. Owing 

 to the limited number of vessels available and lack of time, the experiments were not as 

 complete as they should have been. Still, they may perhaps serve to induce some more 

 fortunately situated observer to carry on the enquiry. To obtain good results, each individual 

 should be placed by itself in a vessel with a considerable quantity of water, which should 

 be frequently changed. It would be interesting to try and induce the animals to feed 

 under water. The few attempts, which I made at this, were unsuccessful. That death is 

 not due to starvation is, however, certain from a consideration of the fact that they will 

 live for weeks without food, if not placed under water. 



3. Some notes on the land crabs of the genus Ocypode. 



i. Ocypode ceratophthalma (Pallas). 



This species lives in burrows in the sandy strand of the lagoon. Large wan'ens of these 

 burrows extend along the shore just below extreme high-water mark. They are thus 

 covered and destroyed at high tide, but during many hours are completely exposed. The 

 mouth of the burrow is not always situated so as to be covered by an average tide, but 

 the lower part always falls in at high water, owing to the loosening of the sand. The 

 crab, which awaits this event at the bottom of its hole, is thus buried for some hours. 

 When the tide falls it works its way out and repairs its burrow, and until the water 

 returns may be seen moving about the shore near the opening^ and running with extra- 

 ordinary swiftness when threatened with capture. Under these circumstances the first impulse 

 of the animal is to make for its hole, but, if cut off from this, it will seek safety in the 

 water. The crabs double readily, and a favourite device with them is to remain still till 

 the pursuer approaches and then suddenly dart off. These manceuvres are carried out on 

 the tips of their slender legs and with the eyestalks raised so as to survey as wide a field 

 as possible, and give the impression that the animals possess intelligence of a high 

 order. When finally seized, they make vigorous efforts to defend themselves with their 

 chelae. 



As might be supposed from their bvirrows being submerged at high tide, and from 

 their readiness to take refuge in the sea, the crabs are able to endure immersion in salt 

 water for a number of hours, though they are eventually killed by it. Fresh water, on 

 the other hand, is rapidly fixtal, two hours being the longest period that any of them sur- 

 vived an experiment. 



The burrows are inhabited each by a single crab, and Major Alcock^ has shown that 

 the stridulating apparatus, possessed by this species in common with most others of the 



1 In this connection it is interesting to note that the stimulation to give a few beats. 

 heart of the common hermit-crab [Eupaiiurus bernhardus " In tlie hottest part of the day, when the sun shines full 



(Linn.)] and the shore crab [Carcinides moenas (Penn.)] may upon the beach, they are less active than at other times, 

 often be found to be beating some time after every outward ^ Alcock, Ann. Mag. N. H. (6), x. (1892). For 0. cerat- 



sign of life is lost from exposure to the air. Even when it ophthalmu see Anderson, Jowm. As. Soc. Bengal, Lv. (1894). 

 has stopped, it may sometimes be induced by mechanical 



