and QH Ji>ix N^/o Spechu of Crustacea, 4*^« X1% 



and the vulva through which the oviducts pass. The ovaries 

 are two oval, club-shaped bodies of considerable size, situated 

 on each side, and rather anterior to the stomach. They are 

 large and rounded anteriorly ; small, pointed, and converging 

 posteriorly. Each oviduct arises from the external margin of 

 the ovary. It may be divided into three parts, the thoracic, 

 abdominal, and external. The first, or thoracic portion, ia 

 very slender ; at the posterior part of the thorax, however, it 

 becomes considerably thicker ; and, in the abdomen, where it 

 makes four or five convolutions, it is at its greatest diameter ; 

 it is considerably contracted as it passes out by the vulva. 

 The external portion is all of the same diameter ; and, when 

 arrived at a state of maturity, it is sometimes longer than the 

 body of the animal. But the length altogether depends on 

 the species. 



The thoracic portion is colourless ; and there a number of 

 small defined objects are seen in it at regular intervals. When 

 it reaches the abdomen these bodies are found to be the im- 

 mature ova ; at this point it is of a delicate carmine colour, 

 and has a striated appearance, from the eggs being placed 

 close together. 



The external oviducts, a short time after the ova have es* 

 caped, drop ofi^, and new ones soon begin to make their ap- 

 pearance. At first the point only is seen jutting out from the 

 vulva, they then gradually increase until they arive at a state 

 of maturity. 



I have not ascertained the length of time which is required 

 before they attain their full growth. Seeing, however, that 

 the distal extremity of the external oviduct is thus first pro- 

 truded, it may be apprehended that the ova contained in that 

 part of the oviduct are first ready for exclusion, and this ac- 

 cordingly we find to be the case. 



The internal structure of the external part of the oviduct, 

 consists of a number of cells placed in a single row, and of 

 the same diameter as the duct ; these cells are formed by a 

 number of strong membranous septa, placed at regular inter- 

 vals. The membranous septa, which divide the oviducts in- 

 to compartments, are of use, in so far as from their strength 

 they prevent the ovum escaping into the empty part of the 



