\. ll\l I. 3 



MIS PARACTW. 



l'u nii.hr with thin .MI.) -month Immi wall : tentacles of moderate length and 

 nf uniform thickness throughout; margin not lobcd ; individual mesenteries uf ea<-li 

 jwir c{ually developed. 



PARACTIS POLARIS. 



One specimen lalx-lK-.l Winter Quarters, 24. 8. 03," anil taken in 25-30 fathoms 

 (PI. I. Kg. 2). 



I Light of column _':; cm.; diameter of foot-dine 3 - 5 cm., diameter of oral disc 

 2'5 cm. Tentacles of uniform size, about 0*3 cm. long, in four cycles 

 12 + 12 + 24 + 48 = 9G. The Itase is adhesive and thin, the insertions of the 

 mesenteries leing visible through it. It in produced all round wider than the column, 

 which narrows considerably. The Imdy-wall in firm, and near the parai>ct somewhat 

 thick, where it is slightly puckered by contraction. The mouth opening is visible in 

 the centre of the tentacles, crowded together by contraction. The a'sophagus is 

 plicated and the two siphonoglyphs arc well marked. 



The sphincter is fairly strong, mcsogloeal, and produced to a fine termination. 

 A transverse section (PI. 1, Fig. 3) shows that it lies nearer to the endoderm, and is 

 reticulate in appearance, giving indistinct traces of layering. (Ireater details of 

 structure are given in Fig. 4. 



The mesenteries are membranous, and the longitudinal muscles are somewhat 

 diffuse, but well marked (PI. 1, Fig. 5). The mesoglooal layer is thin, except close to 

 the body-wall, where the pnrieto-lwsilar muscle arises, but the lamclhu of the muscles 

 are conspicuous and branched. Two cycles of the mesenteries arc complete, and these 

 are fertile, including the directives. The specimen is female, ova in various stages of 

 development lx?ing seen in sections. 



The radial muscles of the oral disc and the longitudinal muscles of the tentacles 

 are mesoglocal (PI. 1, Fig. 6). In regard to this character McMurridi (8, p. 161), 

 in his comments on the genus I\inicti*, states that of two forms of the ' AHutross,' 

 collections which, according to the generally accepted definition of the genus, must be 

 assigned to l'<tmcti, one had these muscles ectodermal and the other mesogloeal, 

 and while raising the question as to whether this character is worthy of generic 

 di-tinction, he places loth provisionally under Paractis. Of the ' Discovery ' specimens, 

 in both the one under consideration and the succeeding one the said muscles arc 

 mesogloeal. 



PARAITIS PAPAVKR. 



Aflttiia papaetr Dnytoo in Dana, p. 148, PI. I. KIL-. 2'., op. cii. 

 Pmrmctit JMJMMT Milne Edwmnto, p. 49, torn. 



A single specimen labelled "Mi.Mmdo Bay, Winter Quarters, 20 fathoms," only 

 slightly contracted, with tentacles, oral disc and oesophageal opening plainly visible, 

 the last-named being 1 *5 ciu. in diameter. 



VOL IV. 



