282 J- Playfair Mc Müerich, 



In tlie contracted individual tliere were also tliree cycles of 

 mesenteries, but the primary perfect cjcle consisted of eight pairs 

 and of these each alternate pair was a pair of directives. The 

 eight primary pairs were sterile, but the eight secondaries and 

 sixteen tertiaries, all of which were imperfect, contained repro- 

 ductive Organs. 



This is, so far as I am aware, the flrst species belonging to the 

 siib-family Fhelliinae in which a departure from the hexamerous 

 arrangement has been observed, and the specifie name which I have 

 chosen for it is intended to denote its departure from the general 

 law\ Its occurrence renders impossible the use of the the words 

 "only six pairs of perfect mesenteries" in the definition of the group ; 

 instead we must write "only the primär}' cycle of mesenteries perfect". 



Genus Chitonanthus McMueeich, 1893. 



Phelliinae with the scapus more or less tuberculate; capitulum 

 ridged; tentacles without bulbous enlargements at the base. 



2. Chitonanthus castaneus n. sp, 



No. 105. Juan Fernandez. 20 — 40 fathoms. 12 specimens. 



The majority of the specimens are strongly contracted, only 

 a few having the tips of the tentacles visible. They have the form 

 of a dorne or low cone, arising from a broad flat base which w^as 

 evidently adherent. The column in some individuals is furnished 

 with numerous tubercles arranged in longitudinal rows extending 

 from near the limbus to the upper margin of the scapus (Fig. 72); 

 the rows are forty-eight in number, the alternate ones having some- 

 what larger tubercles than the others. There is, however, a good 

 deal of Variation in the development of the tubercles ; in some indi- 

 viduals they were quite distinct and conical in form, each being 

 tipped by a small chitinous boss; in others they were low and 

 rounded and lacked any especial development of the cuticle ; in others 

 they were confined to the upper portion of the scapus, wdiile in 

 others again the only indications of their existence was a Single 

 circular row of twenty-four somewhat elongated elevations surround- 

 ing the summit of the contracted column. As a rule the tubercles 

 were more distinct in the smaller individuals tlian in the larger. 



The capitulum was ridged, apparentl}" with twenty-four stronger 

 ridges corresponding in position with the stronger rows of tubercles, 



