CHAP. IX. DEVELOPMENT OF COPEPODA. 85 



through Nordmann, that the same earliest form be- 

 longed to several parasitic Crustacea, which had pre- 

 viously passed, almost universally, as worms ; but the 

 connecting intermediate forms which would have per- 

 mitted us to refer the regions of the body and the limbs 

 of the larvae to those of the adult animal, were wanting. 

 The comprehensive and careful investigations of Glaus 

 have filled up this deficiency in our knowledge, and 

 rendered the section of the Copepoda one of the best 

 known in the whole class. The following statements 

 are derived from the works of this able naturalist. 

 From the abundance of valuable materials which they 

 contain I select only those which are indispensable for 

 the comprehension of the development of the Crustacea 

 in general, because, in what relates to the Copepoda in 

 particular, the facts have already been placed in the 

 proper light by the representation of their most recent 

 investigator, and must appear to any one whose eyes 

 are open, as important evidence in favour of the Dar- 

 winian theory. 3 



All the larvae of the free Copepoda investigated by 

 Claus, have, at the earliest period, three pairs of limbs 

 (the future antennae and mandibles), the anterior with a 

 single, and the two following ones with a double series 

 of joints, or branchiae. The unpaired eye, labrum, and 

 mouth, already occupy their permanent positions. The 

 posterior portion, which is usually short and destitute of 

 limbs, bears two terminal setae, between which the anus 



3 I am still unacquainted with Glaus* latest and larger work, but no 

 doubt the same may be said of it. 



