36 Coelenterata. 



the primary axial polyp becomes blocked by the mesoglcea, which penetrates 

 its base, pushing the endoderm before it. The Gorgonacea may be branched 

 on the same plan as the Alcyonacea and the coelentera of the axial polyps 

 of the first, second and third order become filled from the base by a cornified 

 axis enclosing spicules which however still leaves visible the chambers limited 

 by the mesenteries, represented by the longitudinal vessels to the number of 

 8 in primitive Gorgonacea, 4 or 2 in genera with biradial or bilateral sym- 

 metry. According to his theory the axis is formed independently in each axial 

 polyp and the subsequent union is secondary, a theory -confirmed by Menneking 

 [see Bericht f. 1905 Coel. p 27] and Schneider [ibid, p 29]. 



Versluys( 2 ) describes Bathyalcyon n. robustum n., from fine mud at a depth 

 of 924 m. in the Ceram Sea. The single specimen at first appeared to consist 

 of one large polyp 50 mm. long. In the thick wall there are hundreds of 

 short blind tubes which open to the exterior and bear the ovaries; these 

 are to be regarded as reduced polyps which have lost their tentacles and have 

 no stomodseum. The specimen is therefore a colony consisting of one large 

 sterile autozooid and numerous small, reduced, fertile siphonozooids imbedded 

 in a common but feebly developed ccenenchym. B. is nearly allied to Antho- 

 tnastus and while morphologically a colony, physiologically it is a single polyp 

 in the walls of which the genital organs are imbedded. 



Woodland describes the scleroblasts of Alcyonium digitatum as granular, 

 more or less spherical cells situated at the periphery under the ectoderm and 

 probably derived from the interstitial cells of that layer. The spicule first 

 appears in the cytoplasm as a small spherical concretion and remains ap- 

 proximately spherical in its further enlargement until the division into two 

 of the nucleus. Then the spicule becomes elongated and somewhat dumb-bell 

 shaped and the two nuclei travel to its opposite ends. The dumb-bell becomes 

 amphicoelous by development of a broad rim round the terminal surface of each 

 end, from which two, three, four or more processes are formed some or all 

 of which become afterwards the main branches of the spicule. Other smaller 

 processes may also appear and the spicule assumes a form the ground plan 

 of which is common to all spicules whatever may be their final form. -In all 

 the varied and complex adult spicules only two nuclei are present. After the 

 first elongation of the spicule the nuclei play no further part in determining 

 its form. Organic matter is present in the spicules in the form of an axis 

 with concentric structure, the diameter of the axis, which varies in different 

 spicules, is small in the lancet-shaped or monaxon spicules. No horny spicule 

 sheath was observed. The shapes assumed by the spicules are probably to 

 be attributed to physical causes, the pressure of the mesogloea in the earlier 

 stages and the heterogeneous constitution of the surrounding medium in the 

 later stages being the principal factors. The nearer a spicule is situated to 

 a limiting layer the more regular its form, those in the deeper layers of the 

 mesogloea are more irregular. In addition to the scleroblasts there are in the 

 mesoglceal substance of A. dig. endoderm cells, spherical "jelly secreting" (Bourne) 

 cells, small interstitial cells and nematocysts. There are also oval bodies de- 

 scribed by Hickson and by Bourne ("ovoid bodies") among the cells of the endo- 

 dermic cords; the author finds a cnidocil in connection with such of these 

 bodies as are present near the periphery, they are therefore nematocysts. 



Gravier ( ] ) describes Scytaliopsisn. djiboutiensis n. from the sandy shore of Djibouti. 

 Large specimens are about 12 cm. long. The stem is straight, unbranched, infla- 

 ted below and bears the polyps, grouped into leaves (5 or more polyps in each) 

 disposed in two lateral series. The leaves are separated by wide intervals. 



