20 CERIANTHARIA. 



of the directive chamber. In the latter Danielssen has not noticed that all the marginal tentacles 

 were torn off at the base, as is obvious from Danielssen's figure 7, PI. 5, which is in accordance 

 with the preserved specimen, on which only labial tentacles were found intact The tentacles marked 

 in Danielssen's figure are labial and not marginal tentacles as Danielssen states. Between the 

 marginal and labial tentacles a very large part of the oral disc is devoid of tentacles and shews radial 

 furrows corresponding to the attachments. The stomatodaeum is long and furrowed longitudinally, 

 in the lower part with mesogloeal ridges. The siphonoglyph is narrow with only 2 couples of mesen- 

 teries attached. The hyposulcus is small but well marked. The hemisulci are very long, but narrow 

 and look like filaments. 



Anatomical structure. Though the specimen of C. vogti at my disposal was not internally as 

 well preserved as might be wished, I have been able, I hope, to fix the most important of the larger 

 anatomical details. The lowest part of the animal however was very much macerated, so that I am 

 unable to state whether differentiation of craspedonemes occurs there, though in my opinion it may 

 be taken not to be the case. Consequently I cannot give any diagram, nor is it necessary, as it 

 looks as if the mesenterial arrangement corresponds with that of C. lloyii, although C. vogti has nothing 

 like as many mesenteries as that species. As I did not want to spoil the specimen, the finer ana- 

 tomical details given below are incomplete, and all the more so, that even as regards the tissue 

 the object examined was very much macerated. 



The column is of the usual structure. The ectoderm contains numerous larger and smaller 

 nematocysts with very irregularly coiled thread. Some of the largest capsules reached a length of as 

 much as 72/4 and a breadth of 17^. The ectodermal musculature is not particularly well developed 

 for a Cerianthid. 



The ectoderm of the marginal tentacles contained extremely numerous spirocysts (maximum 

 length oo//) and in addition thick-walled nematocysts (length 24/4 The ectoderm of the labial ten- 

 tacles agrees, as to the occurrence of nematocysts, with that of the stomatodaeum, though the spiro- 

 cysts are much more numerous and the other nematocysts more sparse. The spirocysts are smaller 

 than in the outer tentacles. 



The ectoderm of the stomatodaeum is of the usual structure. The nematocysts consist of very 

 numerous capsules with irregular, strongly coiled thread (length 31 41^ breadth 7^), and in addition 

 are found very numerous spirocysts, small thick-walled nematocysts (length about 24 p) and thick- 

 walled capsules with quite well marked base of the spiral threads. The last are common and attain 

 a length of 43^ and a breadth of 7/4. 



The mesenteries. The directive mesenteries are short with a well marked hemisulcus (see above). 



Protomesenteries 2 go down to the aboral pole, and are fertile, with a long ciliated tract region, 

 which reaches a little further down than protomesenteries 3. Then succeeds a short, poorly developed 

 cnido-glandular tract region and finally a long craspedion region. Protomesenteries 3 are sterile, 

 and attain a length of about '/s of the length of the body between the aboral end of the stomatodaeum 

 and the aboral end of the animal. They are formed like the metamesenteries of the 3rd and 4th cycles. 



The grouping of the metamesenteries seems to resemble most closely that of C. lloydii. The 

 fertile metamesenteries of the ist and 2nd cycles go down to the aboral pole and shew about the 



