CALIGOIDEA. I345 



with great difficulty. In general appearance, each of these glands 

 resembles a piriform membranous sac, with an internal granulose 

 structure. The duct, which is attached on the outer margin, is a 

 slender vessel, of a thin, membranous nature. It continues of a 

 uniform size through the thorax to the central parts of the abdomen, 

 where it gradually enlarges and undergoes a few convolutions. 



A short distance below the convoluted portion, in the abdomen, 

 there is a small oval gland, with well-defined limits, contained within a 

 distinct sac. It is composed of several concentric parts, of which three 

 are very apparent; there are two less distinct. Its interior is a trans- 

 parent globule; the outer coats are less transparent, and the one adja- 

 cent to the interior, the least so. The central part of this gland is 

 connected with a small subcorneous tube, which gradually enlarges 

 and passes into the anterior extremity of the above convolutions. 

 On one occasion, when we had separated this gland and its duct from 

 the abdomen, a fluid, containing particles similar in appearance to 

 those in the blood, rapidly poured out. The convoluted vessel appears 

 therefore to receive the secretions of two seminal glands, and probably 

 corresponds to the vas deferens. Though much time has been em- 

 ployed in searching for the exit of the vas deferens, we are yet uncer- 

 tain on this point. It is presumed, from the appearance of the parts, 

 that it terminates either on the outer surface of the lappet at the 

 extremity of the abdomen, or beneath this organ. 



The ovaries in the female have the same situation and attachments 

 as the spermatic gland in the male (fig. q) . They are however much 

 larger, and extend above the stomach nearly to its centre. They 

 may be distinctly seen through the back shell. They appear to con- 

 tain a long convoluted vessel, which gradually diminishes in size, from 

 its anterior to its posterior extremity. The duct arising from its 

 margin extends without any variation in its size, till it reaches the 

 posterior segment of the thorax, where it gradually enlarges, and 

 continues to increase as it enters the abdomen. In the gravid female, 

 it passes through the abdomen, with a few convolutions, and extends 

 out at the vulva, in the form of a long, whitish, nearly cylindrical 

 membranous tube. This external portion of the oviduct is often a 

 little longer than the animal. 



The vessel in the ovary does not appear to contain divisions indi- 

 cating the presence of eggs ; but the oviduct usually contains eggs 



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