ANASriDACEA I I =; 



the anterior thoracic region. The auditory organ is at the Ijasc 

 of the first antennae. 



Order. Anaspidacea. 



Fam. 1. Anaspididae. — The mountain -shrimp of Tasmania, 

 Anaspides tasniaiiiae, WlIU first described by Thomson ^ in 1893 

 from specimens taken in a little pool near the summit of Mount 

 Wellington ; it was redescribed by Caiman,^ who drew attention 

 to its remarkable resemblance to certain Carboniferous fossils of 

 Europe and ]^. America (Gampsonyx, Palaeocaris, etc.). 



The creature appears to be confined to the deep pools of the 

 rivers and tarns on the mountains of the southern and western 

 portions of Tasmania.^ The waters in which it occurs are always 

 cold and absolutely clear, and there is no record of its living at 

 altitudes much below 2000 feet, while it frequently occurs at 

 -4000 feet. The body may attain upwards of two inches in 

 length ; it is deeply pigmented w^ith black chronia,tophores, and 

 it is held perfectly horizontal without any fiexure. The animal 

 rarely swims unless disturbed, usually walking about on stones 

 and water-plants at the bottom of deep pools. In walking the 

 endopodites of the thoracic limbs are chiefly instrumental, but 

 they are assisted by the exopodites of the abdominal limbs. 



When frightened the shrimp can dart rapidly forwards 

 or sideways by the strokes of its powerful tail-fan, but it never 

 jumps backwards as do the other Malacostraca. It appears to 

 browse upon the algal slime covering the rocks arid on the 

 submerged liver-worts and mosses, but it does not refuse animal 

 food, even feeding on the dead bodies of members of its own 

 species. The thoracic limbs, which are all biramous except the 

 last pair, carry a double series of remarkable plate-like gills on 

 their coxopodites. The slender and setose exopodites of the 

 thoracic lim1)S are respiratory in function, beiug kept in continual 

 motion even when the animal is at rest, and serving to keep up a 

 current of fresh water round the gills. 



Anasindes shows a remarkable combination of structural 

 characters, some of -which are peculiar, while others are possessed 

 in common with the Peracarida or Eucarida. The chief peculiar 



1 Trans. Linn. Sue. (2^, vi., 1894-1897, \k 285. 



- Trans. Roy. Soc. Edinburg/i, xxxviii., 1897, p. 787. 



■'■ (I Smith, Proc. Roy. Soc. 1908. 



