CERIANTHARIA. 



53 



Reproductive organs: All the Ceriantharia which I have examined are hermaphrodite. This 

 seems corroborated by the published accounts of other Cerianthida. It should be mentioned however, 

 that Danielssen speaks of C. borcalis (= C. lloydif) as being bi-sexual. Me. Murrich (1891, 1910) 

 also says that the ovaries and testes are allotted to separate individuals in the case of C. americanus 

 and Packyceriantftus finibriatus. I cannot confirm these statements in the case of C, borcalis and C. 

 nincricanus: both species are hermaphrodite. I have examined several individuals of both these 

 species, and testes and ovaries were always found in the same specimen though not always in the 

 same proportions. Lastly there is Pachyccrianthus fimbriatus, apparently an [exception to the rule. 

 But most likely this species is also hermaphrodite. For I hold it probable that in certain species the 

 different gonads are not mature at the same time, in other words that certain Ceriantharia at least 

 are proterandrous hermaphrodites. The distribution of the sex-organs on the different mesenteries 

 has been treated above. 



4. The mesenterial musculature. 



It is well known that previous investigators of the mesenterial musculature of Ceriantharia, 

 such as the brothers Hertwig, A. von Heider, Me. Murrich, Boveri and others have ex- 

 pressed the most different opinions concerning the arrangement of this musculature (compare Carl- 

 gren 1893 and van Beneden 1898). In a treatise published in 1893 I shewed however that in 

 Ccriautlms lloydii, mcmbranaceus and solitarius and in an unnamed Cerianthid from Greenland ( Ce- 

 rianthus lloydii] the mesenteries at the level of the oral portion of the stomatodaeum bore longitudinal 

 muscles on the side looking away from the directive chamber, whilst the opposite side facing the 

 directive chamber had transverse muscles. Only the directive mesenteries seemed to deviate from the 

 rule, in as much as their very feebly developed muscles take a more slanting course, more transverse 

 in the upper parts of the mesenteries, mostly longitudinal in the lower parts (p. 242 I.e.). Van Bene- 

 den (1898 p. 28) confirmed the arrangement of the musculature in this way in C. lloydii, and Cer- 

 fontaine (1909) in Arachnanthus oligopodus. The former however could not find any muscles on the 

 directive mesenteries, whilst the latter was able to certify, in the species dealt with, the same arrangement 

 of the musculature on the directive mesenteries as on the others. In the larval forms, on the contrary, 

 van Beneden could not discover any definite arrangement of the mesenterial musculature; it varied 

 so much, that v. Beneden came to the conclusion that there was nothing constant in the arrangement 

 of the mesenterial musculature in Ceriantharia, unless it were the absence of a musculature on the 

 directive mesenteries (p. 155). In the year 1900 I refuted van Beneden's contention that the directive 

 mesenteries in this group of animals are without musculature and established the existence of the 

 same arrangement of the mesenterial musculature in C. maua as in C. lloydii (I had not however in- 

 vestigated the directive mesenteries). Having now examined not only A. oligopodus but a number of 

 other Ceriantharia here described (see tables) which are representative of Ceriautharia with "acontia", 

 of those with botrucnidae and of those devoid both of "acontia" and botrttcnidae, and having found 

 a similar arrangement of the mesenterial musculature on all non-directive mesenteries, it seems to me 

 in the highest degree probable that all adult Ceriantharia have the mesenterial muscles arranged in 

 like manner. The longitudinal muscles are situated on the side of the mesenteries 

 looking away from the directive chamber, the transverse muscles on the side facing it 



