736 RECOED or current researches relating to 



of tlie CapitelliclaB, we are now led to ask what is their relation to tbo 

 organs of the same name among the Vertebrata ? Discussing in detail 

 the opinions of those who have busied themselves with the morphology 

 and embryology of the lower Vertebrata, Eisig finds that the abdominal 

 protuberances of Notomastus are comparable to what is found per- 

 manently in Gobius and others, and temporarily in the larvae of other 

 Vertebrata, while the hyaline tubes of the latter group are in Noto- 

 mastus replaced by the defended position of the organs ; so, too, the 

 thoracic organs of the worm correspond to the canals covered in by 

 integument in the Vertebrates. The author is of opinion that the 

 " lateral lines of the Naiades " are not, as Semper thinks, homologous 

 with the system of lateral organs in the Vertebrata. Turning to the 

 goblet-shaped organs, Eisig points out that in the Capitellidte and in 

 the Teleostei there are goblet-shaped organs on the head, in the 

 buccal cavity, and on the trunk of both ; that in both cases they have 

 no relation in their arrangement to the segmentation of the body, and 

 that they are more richly supplied to the buccal cavity and lips than 

 to the trunk, while their structure is exceedingly similar in both cases. 

 Comparing the goblet-shaped organs with the lateral organs wo 

 observe the following points of difference : — 



(1) The former are not, and the latter are, segmental in arrange- 

 ment. 



(2) The latter are chiefly confined to the trunk, and are found 

 only in animals of aquatic habitat. 



(3) The sensory cells of the (Vertebrate) lateral organs are short 

 and pyriform, of the goblet- shaped organs long and filamentous. 



(4) The lateral organs have long hairs, seemingly auditory, and 

 appear to be adapted to a mechanical mode of perception, while the 

 goblet-shaped organs have short hairs, seemingly olfactory, and appear 

 to be adapted to chemical changes. 



There are, however, strikingly similar arrangements in both ; 

 they are both epidermal structures, both form rounded solid pro- 

 tuberances protected by the siu'rounding epidermal tissue, and both 

 contain centrally a bundle of special " sensory cells." The author 

 appears to incline to the view that the two sets of organs have arisen 

 independently of one another from the epidermis. 



We come now to the interesting question of the function of these 

 organs. It has been suggested by Leydig that the system of lateral 

 organs in the Vertebrata forms an apparatus specially adapted to an 

 aquatic habitat, and an organ of a " sixth sense " ; F. E. Schultze 

 inclines to a somewhat similar view, regarding the organs in question 

 as being sensitive to movements in mass of the water, or of solid 

 bodies in the water ; Eisig, however, would look upon the arrange- 

 ments in the way of protection and so on, which are found in the 

 Capitellida), as being means for preventing the contact of solid bodies 

 with the sensory organs. 



As to the goblet-shaped organs, there seems to be but little diflSculty 

 in regarding them as having a gustatory fimctiou ; strange as it may 

 seem to us that these organs should not be distinctly limited to the 

 buccal cavity, it may be pointed out that Schultze regards the similar 



