NEW SPECIES OF EDWARDSIA FROM NEW GUINFA. 519 



Edavardsia willeyana, u. sp. (Plate 51. fig. 5.) 



Scapus not divided into areas by longitudinal grooves corresponding to 

 the insertions of the macromesenteries, but invested by a bright chestnut- 

 brown epidermis marked by numerous, fine, transverse rugse and studded 

 with numerous, colourless, more or less elevated, rounded vesicles or papillae 

 arranged in numerous, irregular, longitudinal rows. No distinct physa, but 

 the body tapers towards the posterior extremity and forms a blunt cone on 

 which the epidermis is very thin and the papillaj more closely crowded 

 together. The capitulum very short, its surface marked by eight deep 

 grooves corresponding to the insertions of the macromesenteries, the areas 

 between the grooves tumid and raised at the edge of the oral disc into eight 

 more or less pointed, marginal tubercles alternating with the bases of the 

 outer circlet of tentacles. Tentacles sixteen in number, arranged in two 

 circlets of eight each ; the tentacles subulate^ very extensile ; in a retracted 

 specimen some are simply infolded over the oral disc, others are partially or 

 wholly invaginated. Eight macromesenteries extending from the oral disc 

 to the posterior extremity^ their retratitor muscles highly developed in the 

 region of and below the actinopharynx, but tapering abruptly to form mere 

 strands of muscular fibres posteriorly. Micromesenteries very minute, with 

 well-developed parietal muscles but no retractors, eight in number, two in 

 each sulculo-lateral, one in each lateral and sulco-lateral macromesenterial 

 interspace. Actinopharynx short, sacculated, with a distinct sulcus and 

 sulculus. No definite sphincter muscle. 



Length of contracted specimen, 40 mm. ; greatest diameter, 6 mm. 



Hah. Straits of Rakaiya, New Britain. 



In this single specimen of E. wiUeyana seven macromesenteries extend to 

 the aboral end, one of the eight being shorter than the others. The aboral 

 end is perforated by seven distinct pores leading into the seven aboral inter- 

 mesenterial spaces. These pores are not visible externally in the spirit- 

 preserved specimen, but can easily be demonstrated in sections. The 

 detailed account of the situation and structure of these pores must, however, 

 be deferred to a future paper. 



II. The Order of Succession of the Tentacles and Micromesenteries 

 in the Edwardsidce. 



I have been able to study the positions of the mesenteries and the 

 relations of the tentacles to the intermesenterial chambers in six species 

 of Edwardsla with some degree of exactitude. In these species the number 

 of tentacles varies from ten in E. mammillata to thirty-two in E. carnea. In 

 every case the number of mesenteries is the same as the number of tentacles — 

 in other words, each tentacle corresponds to an intei mesenterial chamber. 



