DAPHNIAD.E. 73 



extremity of the beak, — an opinion adopted also by 

 Ledermiiller. Schoeffer was the first who showed its 

 true situation, and De Geer confirmed his observations. 

 Schoeffer describes also the two mandibles, and fancied he 

 likewise saw the lips, but could not make them out dis- 

 tinctly, from the smallness of the animal. 



The digestive canal (t. VIII, f. b) commences immediately 

 behind the mouth, in the form of an oesophagus, which is 

 short, narrow, slightly curved, and stretches obliquely 

 forwards and upwards, terminating immediately behind 

 the brain, in the stomach. 



The stomach (f. b, e) is in form of a large vessel, curved 

 at its upper part into a complete arch, nearly straight in 

 its course downwards through the body, and suddenly 

 bending up again in the abdomen. It runs almost all 

 the length of the animal, opening by the anus between 

 the first two dentated arches of the posterior part of the 

 last segment of the body. Immediately behind the eye, 

 near the cardiac extremity of the stomach, we see two 

 vessels (f. b, d), curved upwards, in the form of a letter S 

 reversed, the arch turned towards the eye ; these are 

 described by Schoeffer, who considers them as organs for 

 furnishing the necessary juices for the nourishment of the 

 body. De Geer says they resemble ca3ca. Jurine sup- 

 poses them to be organs proper for furnishing a juice 

 destined to perfect digestion. Straus at first considered 

 them as such also ; but, upon more mature examination, 

 at length concluded them to be really casca. 



The body of the animal is quite free, and unattached 

 within the valves of the shell. It is slender and long, and 

 is divided, according to Straus, into eight segments ; the 

 first of which is the largest, and is the only one which is 

 attached to the valves. At the second segment the body 

 suddenly diminishes in vertical diameter, sinking down, 

 and leaving above a strong projection, formed by the first 

 segment. From this projection, throughout the rest of 

 its extent, the body is unattached to the shell, and leaves 

 a vacant space between it and the edge of the valves, into 



