250 PKOF. A. C. HA.DDON ON - TWO SPECIES OF 



in patches to prove that the zooxanthellae occurred sparsely. 

 The endoderm coating the generative region of the mesenteries 

 (PI. XIX. fig. 6) appears to be of a slightly different character from 

 that of the more distal portion ; in the latter granular gland-cells 

 are very abundant; the mesenterial filaments (craspeda), as 

 usual, contain a large number of granular unicellular glands, but 

 I cannot discover any nematocysts. 



In the capitular region of the body the endoderm is much 

 better preserved, as will be seen from fig. 7 ; it is crowded with 

 symbiotic algse. At this region of the body the muscular folds 

 of the endoderm, which usually remain simple, are very slightly 

 branched (PI. XIX. fig. 7). The mesogloea or "mesoderm" 

 appears to be entirely fibrous, the wavy appearance being due to 

 contraction (figs. 6 and 7). 



The mesenteries are ninety-six in number, the formula being 

 12 + 12 + 24 + 48; all of them are perfect, that is reach the 

 oesophagus ; lower down the mesenteries of different orders can 

 be recognized by their length and relative size of the longi- 

 tudinal muscles, the latter being very well developed (PI. XIX. 

 fig. 5). All the mesenteries bear reproductive organs. The 

 specimen under examination possessed only ova (fig. 6). 



The gonidial grooves are very well developed (PI. XIX. fig. 4) ; 

 above they have thick swollen margins, but lower down the latter 

 are flattened bands. The oesophageal wall is thin, and can be 

 divided into an upper folded portion and into a lower more 

 diaphanous moiety. 



The nematocysts (figs. 8 and 9) vary in size from about '00225 

 to -0035 of an inch, and in breadth from about '00075 to -0013 of 

 an inch. No barbs are to be seen on the proximal portion of the 

 thread. 



There is a certain amount of external resemblance between 

 this species and Cereus pedunculatus (Perm.) (Sat/artia bcllis, E. 

 & S.), at least in such characters as the warty capitulum, smooth 

 scapus, numerous somewhat short tentacles in several rows, of 

 which the outermost is papilliform ; but the latter is a typical 

 member of the, Sagartidffi in having acontia and in the six pairs 

 of primary mesenteries being sterile although others reach the 

 oesophagus. It is possible that the Actinia paumolensis of 

 CouthoUJ is allied to our species; but II. Milne- 1<]<1 wards and 

 Andrefl botl agree; in placing that spdeies close to the above- 



