CRUSTACEANS. J.'T 



each - 'In- head. Tin- u-u:il colour of tin- animal is diniry white 



throughout. 



'I'll-- tour I'.iir "T ii|.|n-r members resemble a rich furred mil', in line 

 -periineng ; but. in jxx>r specimens, the fringe clothing them is little 

 nion- than percept il>le, it' these are to be accounted limbs, the whole 

 complement, including the six posterior members, is fourteen, \vhich may 

 have IIH! some observers to consider the Astacilla a species of Onisens. 



v singular, aggravated, perhaps, ]>\ apparent < \ 



traordinury disproportions. The position frequently assumed, and Ion;: 

 retained, is adhering by tin- hind legs to any foreign substance, with tin- 

 head downward*. 1 have never seen any specimen attempt to swim, to 

 which, indeed, its general form is quite adverse. 



PLATK I.XI1I 



>'[r;s. 1, 2. Attacilla, natural >izc, fig. 10, enlarged. 



'I'd.- exuviation of a specimen took place during the firnt week of 

 October, when the shell was detached in two portions, the. post < -rior com- 

 prehending the six hind limbs. 



The season of propagation extends from March to December. The 

 union of two fine large specimens seemed to ensue on the 12th of this 

 latter month : ova appeared June 14th, on the thorax and abdomen of 

 another specimen. But the presence of a diminutive white 7xx>phyt* 

 injured the roe, which proved abortive of progeny. 



As the position of the spawn is not exposed to view it certainly re- 

 mains attached to the parent, while the young quit the capsules, and arc 

 seen running about the vessel. 



A full grown specimen having reached me on March 21, a suitable 

 vessel received it. Herein I was much surprised next day to find above 

 sixty young, which had been recently produced. All were pun- white 

 they exceeded a line in length : their black eyes were rath and 



they entirely resembled the form of the parent. 



Some riivumstancesare perplexing, especially regarding the numlK-r. 

 for it may be qi; 1 \\hether some had not Ixx-n concealed, - 



tached miobsei . 



