488 . THE MICROSCOPE. 



mass." The muscular fibre, however, is wanting in those 

 distinct transverse striae, so fully developed in the muscle 

 of the higher orders of animals. 



The ova of the compound Actinias are of a rounded 

 form, often brilliantly coloured, and their embryos, by a 

 series, of gradual changes, finally assume the appearance 

 and condition of the parent. Milne Edwards, to whom 

 we are indebted for most of our knowledge of the repro- 

 ductive processes of actinozoa, insists on the necessity of 

 distinguishing between that of gemmation and fissura- 

 tion, the polype-bud at first being no more than a pro- 

 tuberance from the parent "enclosing a csecal diverticulum 

 of the somatic cavity." Both simple and composite Fun- 

 gidce occur, and multiply by lateral gemmation. 



The Gorgonidce differ from all other Alcyonaria in 

 having an erect branching caenosarc so firmly rooted that 

 they are reputed to rival oaks in size ; but it is doubtful 

 whether they ever attain to a height of more than five or 

 six feet. 



Pennatulidce. This family derives its name from 

 penna, a quill, and the spicula closely resemble a pen, one 

 of which is represented in fig. 239, No. 1. The polypes 

 are fleshy white, provided with eight rather long retractile 

 tentacula, beautifully ciliated on the inner aspect with two 

 series of short processes, and strengthened moreover with 

 crystalline spicula, there being a row of these up the 

 stalk : the series of smaller processes are ciliated. The 

 mouth, in the centre of the tentacula, is somewhat 

 angular, and bounded by a white ligament, a process from 

 which encircles the base of each tentaculum, and thus 

 seems to issue from an aperture. The ova lie between the 

 membraneous part of the pinnae ; they are globular, of a 

 yellowish colour, and by a little pressure can be made to 

 pass through the mouth. 



Dr. Grant writes : "A more singular and beautiful 

 spectacle could scarcely be conceived than that of a deep 

 purple Pennatula phosphorea, with all its delicate trans- 

 parent polypes expanded and emitting their usual brilliant 

 phosphorescent light, sailing through the still and dark 

 abyss, by the regular and synchronous pulsations of the 

 minute fringed arms of the polypes." The power of 



