320 zoology of seaham harbour. 



2. Description of the Zoea of Portunus depurator. 



On tlie 23rd July a female crab (Portunus depurator) was cap- 

 tured at sea, by means of a surface net, its capture being 

 determined on, on account of the very peculiar appearance it 

 presented as it floated on the surface. 



On being placed in a jar of sea-water it was seen to be laden 

 with spawn, which formed a large ball, attached to the abdomen; 

 its actions then became so excessively violent as to cause the 

 dispersion of the larvae in countless numbers ; in fact, so numerous 

 were they that the water appeared more like thin "oatmeal gruel" 

 than anything else. 



* I was much surprised to find that each particle of " oatmeal" 

 was an active little crustacean of most grotesque shape dashing 

 about in the water, by means of the movement of a tail-like organ ; 

 this was bent under the body, and then pushed out, throwing the 

 animal forward. 



On arriving at home these interesting forms were removed to 

 larger vessels, containing fresh sea-water; but on the following 

 morning very few of them were alive. Fortunately one batch 

 was all right, and this was shortly after removed to a large flat 

 dish, forming a very good artificial pool. Being determined to 

 use every endeavour to keep them alive, and if possible to mark 

 the further changes of this animal, day after day I watched them, 

 made sketches, and anxiously hoped for some appearance of change, 

 but it soon became evident that the numbers were fast decreasing 

 without a chance of witnessing the transformation from a zoe to 

 a megalope. 



The fourth day after being captured not one living specimen 

 could be found, which was much to be regretted, as the chance 

 of obtaining larvae of this class is not often within reach. 



A reference to the sketches and appended notice wdll explain 

 the general appearance and peculiarities of this strange form. 

 Unfortunately, animals of this kind cannot on every occasion be 

 induced to place their limbs in either a graceful or natural posi- 

 tion. The consequence is, that, in this instance, the sketches of 

 the whole body do not exhibit the correct position of the legs, 



