Introduction to A 7i imal Morphology. 3 4 1 



of cones, but is usually divided, each cone having its 

 own hexagonal corneal lens or facet. Eye-like sense- 

 organs, or, at least, red shining spheres, are distri- 

 buted on the sides of the thoracic legs of some, or 

 between the four anterior abdominal swimming feet. 

 In Podophthalms the eye is mounted on an un- 

 jointed stalk, considered by some as a true limb. 



Cirripedes are hermaphrodite, the ovaria and testes 

 being branched pouches, only distinguishable by their 

 products. In Barnacles the ovary is in the stalk, and 

 is formed in an outgrowth of the mantle, into whose 

 cavity it opens at the base of the first pair of cirri. In 

 Balani they are imbedded in the mantle, the testes 

 surround the digestive canal, and the vasa deferentia 

 accompany the intestine, and often unite and open at 

 the post abdomen. In free Copepods the ovary or testis 

 is single, central, lying on the intestine. There are 

 two oviducts, one on each side, opening either sepa- 

 rately or together, and having their hinder part often 

 dilated into a uterus, or having a series of egg-holding 

 caeca (Corycseidae). The wall of the last part is gland- 

 ular, or a gland lies on it which secretes an adhesive 

 material whereby the eggs are united in clusters, and 

 carried by the female beneath the abdomen. There is 

 often a terminal receptaculum seminis. Some parasitic 

 Copepods have a double ovary, and the testes are 

 either similar or single, with a double tortuous vas 

 deferens, dilated at its end into a vesicula seminalis, 

 in which the spermatozoa are cemented into sperma- 

 phores, and with a papillary end which may act as a 

 penis. Sometimes the right vas aborts (Pontellidse, 

 Calanidse). In Branchiopoda the ovary is either mul- 

 tilobar or a series of pouches along the intestine. In 



