546 Transactions. 



eggs which he artificially fertilised. Being at the time ex- 

 tremely busy with other and more important work, he kept 

 neither record nor drawings of these eggs. On the 16th Octo- 

 ber, the temperature of the water in the hatching-house being 

 6° C, some of the eggs were ready for hatching out, the larvae 

 showing in a well-developed condition, the eyes and pectoral fins 

 being especially prominent (Plate LVI, fig. d). The specimen 

 figured was just about to hatch, and the larvae when liberated 

 floated with the yolk-sac uppermost. By the sixth day the 

 yolk-sac was nearly absorbed (fig. e), and the little fish were 

 swimming about freely, with much of the slow motion charac- 

 teristic of the adult. The development could not be followed 

 further on account of the numbers of other fry to be attended 

 to. 



, . I 



• ! Crustacea. 



Some experiments were made in regard to common forms 

 of Crustacea, which may be placed on record here, though the 

 results have not been worked out yet. 



Heterograpsus sexdentatus, Milne-Edwards, is one of the com- 

 monest of shore-crabs, and is found under stones between tide- 

 marks. A berried female kept in an aquarium jar spawned on 

 the 28th August, 1904. The zoeae swarmed in the water, and 

 the parent crab immediately commenced to eat them up whole- 

 sale. The development was not followed out. 



Petrolisthes elongatus, Milne-Edwards, is another extremely 

 common form in similar localities. Berried females in an 

 aquarium jar spawned from the 17th to the 23rd November. 

 The zoeae were watched from day to day, and a fairly complete 

 series was obtained and preserved. There has not been time 

 to work out the results as yet. The water of the bay was full 

 of zoeae for some weeks. 



Palcemon affinis, A. Milne-Edwards : This is the common 

 small prawn of the harbour. A single berried female liberated 

 its ova — about three hundred — on the 15th January of this 

 year. The larvse were very active, darting about in all parts 

 of the jar, but invariably seeking towards the light side. Their 

 cannibal propensity was very marked from the first, a feature 

 apparently of all larval Crustacea, as well as of a good many 

 adult forms. If not liberally supplied with minced cockle, 

 which they ate greedily, they at once attacked each other. The 

 development was watched from the 15th January to the 22nd 

 April, a period of ninety-seven days, during which they under- 

 went eleven moults. The dates of these moults were as follows : 

 First moult, 20th January ; second moult, 26th January ; 

 third moult. 2nd February : fourth moult, 6th February ; 

 fifth moult, 11th February; sixth moult, 15th February; 



