NO. 25 



A NEW ACTINIAN CARLGREN 



a part of the capitulum and oral disk was torn off, there may have 

 been 12, possibly arranged in a single cycle. They are cylindrical, with 

 their apex acuminated and rather robust. The structure of the tentacles 

 shows nothing extraordinary. Their longitudinal muscles and the 

 radial muscles of the oral disk are ectodermal and well developed. The 

 evaginated actinopharynx is provided with 12 longitudinal ridges sup- 

 ported by folds of the mesogloea. The ectoderm is high and provided 



Fig. 2. — Halcampogeton papillosus. 

 Transverse section of the pennon of a 

 dorsolateral mesentery. 



Fig. 3. — Halcampogeton 

 papillosus. Transverse sec- 

 tion of a parietal muscle in 

 the region of the actino- 

 pharynx. 



with numerous gland cells, its mesogloea thin. There are no distinct 

 siphonoglyphs. There are 12 mesenteries below the actinopharynx and 

 probably not more in the distal part of the body. I have cross-sectioned 

 a piece containing six mesenteries in the region of the tentacles. Of 

 these, the dorsal directives and three others were perfect ; one, form- 

 ing a pair with a perfect dorsolateral mesentery, was imperfect and 

 without pennon. To judge from the arrangement of these mesenteries, 

 there is no second cycle of mesenteries here and only the " Ed- 



