278 J- Playfair Mc Murrich 



No. 508 tliere were six pairs of perfect mesenteries biit only one 

 pair of directives; the secoiid cycle consisted of 01Ü3' five pairs 

 and the third cycle of ten pairs instead of eleveii as mig-lit liave 

 beeil expected, the inissing members beiiig those of the primary 

 exocoel from which the secoiid cycle pair is waiitiiig*. 



The parieto-basilar and basilar muscles are practically wanting, 

 at least no marked mesogloeal processes are developed for their 

 Support. No reproductive organs were visible in the specimens 

 examined. Acontia were present bnt by no means abundantly. 



The assignraent of this form to the genus Meiriclinm is opeii 

 to question but the existence of a collar seems to indicate an 

 association with that genns. In not a few respects the species 

 resembles Sagarfia lohata Caklgren (1899) and inight be regarded 

 as identical were it not that Carlgren refers his species to the 

 Sagartiinae while in all the individuals of the present one that were 

 examined only the primary cycle of mesenteries was perfect. 



Genns Aiptasia Gosse 1860. 



Metridiinae with markedly entacmaeous tentacles; no collar; 

 cinclides arranged more or less regularly around the niiddle of the 

 column, sphincter very weak mesogloeal or eiidoderaial. 



19. ? Aijytasia sp. ? 

 No. 364. Tnmbes. 1 specimen. 



The Single individnal of this species (Fig. 69) was evidently 

 immature. The base was adherent and smaller in diameter than 

 the column which was cylindrical, thongh somewhat irregnlarly 

 folded longitudinally, probably as a result of contraction. No 

 cinclides nor Verrucae were observed. The outermost tentacles were 

 mnch smaller than the inner ones and were seated on the margin; 

 the inner ones were of moderate length, slender and cylindrical. 



The column measured 4 mm in height, with a diameter at the 

 base of 2.5 mm. It had a uniform brown color, but it seems probable 

 that was entirely due to preservation. 



Structure. The Single specimen was ciit into transverse 

 sections from which it was seen that the column mesogloea was 

 sligthly thinner than the ectoderm and that the circular muscles 

 were but feebly developed. A weak mesogloeal sphincter was 

 evidently present immediately below the margin, but the direction 



