CERIANTHARIA. 21 



same proportions among the various divisions of the filaments as in that species. The ciliated tract 

 region is long, the cnido-glandular tract inconsiderable and the craspedion region long. 



The metamesenteries of the 3rd and 4th cycles are sterile and developed as in C. lloydii. The 

 metamesenteries decrease considerably in length towards the multiplication chamber, but whether any 

 break occurs in the uniformity of decrease I cannot say with certainty, at least there is no very 

 marked break of the kind. 



The region of the median streak looks very much like that of C. lloydii and is of about the 

 same extent Certainly the ectoderm is much macerated, yet from the appearance of the mesogloea 

 in the filament it may be concluded that the filament was constituted very much as in C. lloydii, the 

 mesogloeal lamellae issuing from the main lamella of the mesentery. An initial partition of the 

 median streak takes place here also, though perhaps the ciliated groove between the two portions of 

 the median streak is less well marked. The spirocysts are very numerous, and there occur besides 

 a sprinkling of thick-walled nematocysts with plainly marked bases of the spiral threads (length 

 about 29 (i). 



The cnido-glandular tract on the metamesenteries of the ist and and cycles is feebly developed, 

 to about the same degree as in C. lloydii. Besides very thinly scattered spirocysts are found numerous 

 thick-walled nematocysts of the same size and appearance as in the median streak. 



The region of the craspedion was badly preserved, so that it was impossible to get an adequate 

 idea of its structure. 



The particular specimen examined was hermaphrodite. Danielssen declares the species to 

 be bi-sexual, but this is not so. The same author makes several other strange statements, amongst 

 the rest about the mesenterial musculature. As far as I have been able to make out, C. vogti does 

 not deviate in general structure from the other Ceriantharia. 



Systematic Remarks. It admits of no doubt that C. vogti and C. abyssorum are the same 

 species. Danielssen says, "that C. abyssorum differs from C. vogti is probable from the number and 

 nature of the tentacles, from the colour of the long tube in which the animal dwells, and finally, from 

 the extremely different locality in which it was foiind". These characters however are not such as 

 to serve as a valid ground of division for the erection of two distinct species. To take the number 

 of the tentacles in the first place, the coincidence here in the two species is almost exact. It must 

 be borne in mind however, that Danielssen omitted to observe that all the marginal tentacles in 

 C. abyssorum had been torn away and only the labial tentacles left (see above). The colour is ap- 

 proximately the same. The other two characters have no significance as distinguishing marks. 



C. vogti seems in its internal structure to recall C. lloydii very closely, though it has a narrower 

 siphonoglyph. But externally the two species are very different. C. vogti has deep furrows in the 

 distal portion of the column, which do not appear in C. loydii; in proportion to the size of the animal 

 the tentacles are considerably longer in the former than in the latter. In C. vogti is found a directive 

 labial tentacle which is absent in C. lloydii: on the other hand there are no labial tentacles in C. vogti 

 issuing from the chambers contiguous to the directive chamber, whilst C. lloydii is in this respect of 

 the normal structure. 



