Mr. J. E. Diierdeii on the Genus Alicia. 217 



few or no neraatocysts. The mesogloea is very thin and the 

 endodermal muscle very weak, except towards the periphery 

 of the disk. Here, close to the tentacles, the disk in spirit- 

 specimens has a deep fold ; the mesogloea is plaited somewhat 

 as at the sphincter muscle, and the endodermal muscle is 

 clearly seen. Nematocysts occur in the fold. 



(Esophagus. — The ectoderm of the oesophagus possesses 

 numerous large elongated nematocysts, which do not stain; 

 the mesogloea has increased considerably in thickness and 

 the endoderm has what seem to be glandular cells. A weak 

 endodermal muscle is present. There is no indication of a 

 groove opposite the directives. 



Sphincter Muscle (PI. IX. fig. 1). — The sphincter muscle 

 is weak, endodermal, and diffuse in character. It is very 

 elongated, extending from just below the tentacles to where 

 the vesicles commence. The mesogloea is thrown into delicate 

 plaits to support it. 



Mesenteries (PI. IX. fig. 4). — The mesenteries are few and 

 regular in arrangement. There are six pairs of perfect 

 mesenteries, two pairs of these being directives. Alternating 

 with the perfect mesenteries are six pairs of secondary 

 mesenteries, and with these again twelve pairs of tertiaries. 

 In structure they are very thin and delicate, except where the 

 retractor muscle is developed. Here the mesogloea is 

 thickened and becomes plaited in a more or less delicately 

 dendriform manner to support the weak muscle-tibres. There 

 is also a weak muscle on the side opposite the retractor, and 

 in the lower part of the column the muscle and plaitings of 

 the mesogloea are about equally developed on each side. The 

 endoderm is feebly developed and has small deeply staining 

 cells. 



Gonads. — In the specimens examined there were no gonads 

 present. 



References. 



(1861) Johnson, J. Y. — " On the Sea-Anemones of Madeira." Proc. 



Zool. Soc. 1861, p. 298, and Ann. & Mag. Nat. Hist. (3) ix. 



1802, p. 177. 

 (1869) Verbill, A. E.— "Notes ouRadiata." Trans. Connect. Acad. 



vol. i. p. 471. 

 (1884) Andres, A. — 'Le Attinie,' p. 224, pi, vii. 



(1888) Hertwig, R — "Report on the Actiniaria.— Supplement." 



Report H.M.S. ' Challenger,' vol. xxvi. 



(1889) McMuRRiCH, J. P. — "Actiniaria of the Bahamas." Amer. 



Journ. Morphol. vol. iii. no. 1, p. 22. 

 (1893) Haddon and Shackleton. — "Description of some new Species 

 of Actiniaria from Torres Straits,' Proc. Roy. Dubl. Soc. 

 vol. viii, (n, s.) p. 128, 



