246 Dr. J. Young on the Mdlacostraca of Aristotle, 



(Kepara, horns), which in Astacus are said to be six, the inner 

 bifid pair being counted as four, their single basal stalk being 

 overlooked. These are not spoken of as organs of touch, their 

 use as weapons of war being the only one assigned them. In 

 the ordinary movements of the animals, they are applied to the 

 sides j but, when alarmed, they are projected while the animal 

 retreats. The mouth, with its two teeth, which are constant in 

 all Malacostraca, next follows. Between the teeth is the tongue, 

 which, as an organ of nutrition, is said to be necessary in all 

 animals (De Part. iv. 5). Beneath the mouth and above the 

 pincers or ^^ great feet " are limbs whose position is not quite 

 correctly stated, while their functions are very vague. The two 

 hairy feet with their thin appendages are evidently the third pair 

 of jaw-feet with their flagella : they are below the mouth ; but it 

 is said that a little below them are other hairy branchioid organs, 

 numerous in Carabus. They are in constant motion ; their 

 function is the reception and emission of water (H. An. iv. 2; 

 De Part. iv. 8). These are clearly the first and second pairs of 

 jaw-feet, with their appendages, placed below the third pair by 

 confusion of the normal position of the animal with that in 

 w^hich it was placed for examination. This description of the face 

 is drawn from Astacus. In the following chapter (H. An. iv. c. 3) 

 the parts of Carcinus are sketched, and the first pair taken from 

 among the branchioid parts, and called the sheaths of the teeth 

 {iTTLKokv/ii/jLara eirl tmv oSovtcov) . Upon the passages iv. 2. 30 

 and iv. 3. 3, as well as upon each other, commentators have be- 

 stowed much labour, learning, and sarcasm. The text is certainly 

 obscure, the terms somewhat indiscriminately used ; but much 

 of these ponderous treatises might have been spared, had it been 

 borne in mind that accuracy was impossible to a writer who 

 denied the existence of respiration in these animals (De Part, 

 iv. 5), and who makes no mention of the branchiae or their cavi- 

 ties, who even denies their existence, as appears from this pas- 

 sage (H. An. viii. 2.4) : — " Those blood-possessing animals which 

 use the water in a fashion analogous to respiration have branchiae j 

 those using it for the sake of food have a tube [blow-hole]. 

 Similarly the Malakia and Malacostraca ; for these imbibe the 

 water for the sake of nourishment.^^ That the branchiae were 

 not included under the hairy branchioid oral appendages appears 

 from this passage (De Resp. 12): — "The Carabi and Carcini 

 discharge the water by the hairy members through the sheaths 

 {irapa tcl Baaea 8ia tmv €7n7nvy/jLdT0)v)J' The following literal 

 translation of the two passages in the ' History' seems the best 

 that can be made of them : — '^ All these animals admit sea-water 

 by the mouth, and gradually contracting this part, discharge it, 

 (as do) Carcini and Cai^abi by^ the branchioid members; now 



