68 Miscellaneous. 



of cortceiitric lines of the surface of the scale there is a region of 

 peculiar appearance, which M. Agassiz designates the " centre of 

 growth," and Maudl the " focus," by which he understands " focus 

 of nutrition." M. Agassiz regards this region as the oldest portion 

 of the scale, the layers of which have been worn away. As regards 

 the first point, that of age, he is undoubtedly right ; as regards the 

 second, tliis is not the case. If the asperities are less prominent in 

 this part of the scale, it is because they date from a period when 

 the fish was smaller. — Anliiv fur Anat. Phys. und wiss. Medizin, 

 18G8, p. 729 ; Bibl. Univ. November 15, 1869 : Bidl. Sd. pp. 276- 

 278. 



On the Anatomy of the Alcyonaria. 

 By MM. G. PoucHET and A. Mtevre. 



The anatomical systems of most of the inferior animals have not 

 even yet been clearly determined. The existence of distinct mus- 

 cular elements in particular, long admitted upon the testimony of 

 the movements which one sees executed by the animals, has only 

 been demonstrated quite recently in the Actinice by M. Schwalbe. As 

 to the Alcyonaria, M. C. Genth has indeed described the muscles of 

 Solenogoryla tulndosa ; but his description is very incomplete, and 

 even it does not stand in any relation to what we have been able 

 to make out of the muscles of two other Alcyonaria, Alcyonium 

 digitatam and A. palmatum. 



The muscular elements are pale fibres, soft during life, about 0*002 

 millim. in diameter when they are at the maximum of contraction, 

 but usually much more slender. They are finely granular, without 

 nuclei, and have distinct outlines. They may easily be isolated, at 

 least in part of their length, which is variable. These muscular 

 fibres are, by their appearance and size, very like those of the 

 Nemertea. These fibres, in the Alcyonaria, are arranged sometimes 

 in sheets, and sometimes in thicker or thinner bundles, which form 

 true muscles, having sometimes very definite insertions, and needing 

 to be described and named as so many primary organs. 



Ist. Lonyitudmal Muscles. — They are eight in number, and corre- 

 spond to each of the mesenteroid laminte, which they themselves 

 assist to form. They extend from the peristome far into the coenen- 

 chyma {sarcosome of M. Lacaze-Duthiers), which we find still 

 very distinct upon the walls of the wide canal, which forms a con- 

 tinuation of tlae bodies of the polypes {grossere Saft-Eandle of 

 Ktilliker). 



2nd. This canal presents throughout, beneath the epithelium 

 which lines it, a layer of circular or transverse fibres, covering and 

 crossing at right angles the fibres of the longitudinal muscles lying 

 against the substance of the cceneuchyma. Those fibres, retaining 

 their direction, give form to the mesenteroid laminae ; and they 

 are to be found still, under the same conditions, even on the wall 

 of the perigastric cavities. 



3rd. Sphincter. — This muscle occupies the peristome. It is formed 



