35 



The fact that spawning in general with reference to this and 

 other groups is an annual event has led naturally to the conclusion 

 that all the mature individuals spawn every year. But it is 

 becoming plain that this is often more apparent than real. 



Further information with regard to the crab will be found 

 in Williamson's papers in the 18th, 21st and 22nd Annual Reports 

 of the Fishery Board for Scotland and in the reports of the Culler- 

 coats Laboratory for many of the years between 1898 and 1916. 



Mr. Waddington kindly drew my attention to a series of a 

 male Mamaia (Maia) squinado which he presented to the College 

 of Surgeons. The first stage was found on August 18th, 1902, 

 the first moult took place on October 21st, and the subsequent 

 history according to the table I now give. I have to thank R. H. 

 Burne, of the College of Surgeons, for the measurements : — 



It is a tropical species common throughout the Mediterranean 

 and the neighbouring Atlantic, and reaches the southern coasts 

 of Britain. How far, and from what point, the larva had been 

 drifted which yielded the specimen found by Mr. Waddington 

 at Bournemouth we cannot tell. But it is evident from the 

 irregularity of the instars that the conditions are not favourable 

 at the northern limit of its range. No doubt the instars would be 

 shorter in warmer southern waters, but even so it is wprth noting 

 that the spider crabs, as evidenced by this exam]ple, do not reach 

 maturity until after the lapse of several years. 



Anomura. — A Waddington series of the common hermit 

 crab, Eupagurus bernhardus, is preserved in the British Museum. 



