362 



ox THE AXATOMY OF A SUPPOSED NEW SPECIES 



Figure I. Diagrammatical transverse section through a single completely retracted polyp 

 in six different planes shown approximately in Fig. II. 



The section is that of a single lateral sextant (or system) — without directive mesenteries — 

 of the same polyp traced downwards in a series of transverse sections. 



The sextant is taken from the middle of one primary septum to the middle of the 

 next. (The position of the sections will be readily understood by reference to Fig. II., but 

 the polyp, from which this figure was made, was not quite in the same state of retraction.) 



The corallum is dotted and covered everywhere by the calicoblastic ectoderm, structureless 

 membrane or lamella, and endoderm. th. Theca. I, II and III. Primary, secondary and 

 tertiary septa. coL Columella (only seen in F). e. w. Body-wall (consisting of ectoderm, 

 structureless membrane and endoderm) external to the mouth-disc or peristome. Limited by the 

 bases of the tentacles, p. w. Body-wall of mouth-disc or peristome, st. iv. Body-wall of the 

 stomodoeum, much thickened owing to the very thick ectodermic epithelium. T. 1, T. 2, 

 and T. 3 Completely retracted primary, secondary and tertiary tentacles covered with batteries 



