AGASSIZ AND WOODWORTH : VARIATIONS IN EUCOPE. 123 



In the increase and special arrangement of the otoliths in the sense 

 organ of Eucope we find the first trace of the specialization of the sense 

 organs of such genera as Oceania, Tiaropsis, and the like. 



There were no variations noted in the shape of the digestive cavity, 

 or in the number of actinal lobes of the manubrium,^ even in specimens 

 with five or six radial canals in place of the normal number (four) o 

 radial canals. The actinal folds were always found to be four in number. 

 In one case only have we found the radiating canal originating from the 

 circular canal. (Plate VIII. Fig. 19.) 



The origin of the peculiar club-shaped intertentacular appendages 

 characteristic of Halopsis and Laodicea, as well as the spur at the base 

 of the tentacles in many ^quoridse, may be referred to the spur-like 

 appendages of the marginal tentacles of Eucope figured in Plate VIII. 

 Figs. 4-13. 



And it may not be far out of the way to look upon the coalescence 

 of adjoining marginal tentacles with sense organs as the first indication 

 of such structural features as the radial marginal tentacles of Eucheilota, 

 or even of Boungainvillia, Margelis, or jS'emopsis. 



It is interesting to note that in Echinoderms there are five radial canals, 

 and four or six or more are considered monstrosities, while in Acalephs 

 four or its multiples are the normal number of radial canals, and five or 

 less are variations. 



The specimens of Eucope showing numerical or structural variations 

 were as a rule fully developed males or females, the eggs and sperma- 

 tozoa being apparently in a healthy condition. 



It would be an interesting study in heredity were it possible to breed 

 the variations in Eucope here enumerated, and ascertain how far the 

 structural chai'acters acquired in the variations we have observed can be 

 transmitted, and lead perhaps finally to the formation of types which 

 we have been accustomed to look upon as having no structural relation 

 with the genus. 



But it is also possible that in a comparatively simple genus like 

 Eucope these variations are not necessarily to be considered as heredi- 

 tary ; they may indicate possibilities iu mechanical combinations which 



1 Variations in tlie manubrium have been observed in Tubularian Hydroids, such 

 as Lizzia, Dysniorphosa, Hybocodon, Dipurena, and Sarsia ; but as they are usually 

 connected with phenomena of reproduction and of budding they have only a dis- 

 tant connection with the Ihie of the present investigation. See an interesting 

 paper by Hartlaub on the reproduction of the manubrium of Sarsia, in Verliandl. 

 d. Deutschen Zool. Gesell., 1896. 



