14G THE VOYAGE OF H.M.S. CHALLENGER. 



10. In some genera the inner surface of the integument is covered by a net-work of 

 nerves and ganglia in connection with, and most probably issuing from, the integu- 

 mentary nerves given off by the supracesophageal ganglion. 



IL In the most primitive condition the eye of the Pycnogonid consists of a rounded 

 transparent part of the integument, the inner surface of which is furnished with some 

 small ganglia and nerve-fibres issuing from the integumentary nerve bundle. The highly 

 developed eye of the shallow-water species shows ganglionic cells, distinct retinal rods, 

 and a lens consisting of a thickened part of the chitinous skin of the animal. 



12. Those eyes which have lost their pigment and their retinal rods are rudimentary. 

 They cannot be considered as forming the transition between the highly-developed eye 

 and its most primitive condition. 



13. That part of the oesophagus which runs through the proboscis has the function of 

 a masticating apparatus. Where the oesophagus enters the intestinal tract (the stomach) 

 small glands (pancreatic, most probably) are present. 



14. The original condition of the genital glands is in the form of a U-shaped mass, 

 placed above the intestine and giving off branches which penetrate the legs. Whereas for 

 the male glands the original form prevails in most (all ?) genera, for the female glands it 

 seems to be a rule that only the lateral parts entering the legs are developed. The genital 

 pores of the females are larger than those of the males ; they are found ventrally towards 

 the extremity of the second joint of the leg. Whereas for the females it is the rule that 

 these pores are present on aU the legs ; it often happens in the males that they are only 

 present on the two or three hindmost pair of legs. 



15. There are always distinct vasa efferentia, but there are not always true oviducts. 



16. In Nymphon hrevicaudatmn, Miers, females also bear the eggs on the ovigerous legs. 



17. The larva creeping out of the egg is already furnished with an azygous outgrowth 

 of the region surrounding the mouth (the proboscis). As a rule in that stage only three 

 pairs of ajjpendages (the later cephalic ones) are present. 



18. These larvae are often furnished on their mandibles with an apparatus producing a 

 single or numerous threads, wherewith the young is attached to the ovigerous leg of its 

 parent. 



19. About the relation in which the Pycnogonida stand to either the Crustacea or 

 the Arachnida we know as much or as little as we do about the relation in which these 

 two classes Arthropoda stand to each other. 



Note. — While I was engaged in preparing the index of this report, and after the 

 rest of it had been printed off, Mr Edmund B. Wilson of Baltimore kindly sent me two 

 papers which he had recently published. In one (the Pycnogonida of New England and 

 Adjacent Waters, Eeport of the United States Commissioner of Fish and Fisheries, part 

 vi. for 1878, pp. 463-506, pis. i.-vii.) the author gives an account of the present know- 



