REPORT ON THE ALCYONARIA. XXxix 



Dasygorgidfe 



Isidae Primnoidae Muriceidae 



I 

 Plexauridje 



I . 

 (iorgonidsR 



Gorgonellidee 



Family V. D a s Y G o u G i D .«. 



In the species of this fiimily the colonies are simple or branched, with a horny 

 calcareous axis ; the ccenenchyma is thin and the polyps are large and distant from one 

 another ; the polyps are not retractile, and in rest simply curve their tentacles over the 

 oral apertures. Both the ccenenchyma and polyps contain simple smooth calcareous 

 needle-like or spindle-like spicules, or semi-opaque scales which are. continued on to the 

 tips of the tentacles. 



The Dasygorgidse represent in many ways the simplest type of Holaxonia. The axis 

 is either simple, rod-like, and unbranched, or else ramified in such a way that from the 

 main axis lateral branches are given off, which may again bear twigs. The axis springs 

 from a calcareous basis which is sometimes ramified in stolon-like processes and sometimes 

 becomes a simple Hatly expanded disc. The axis itself is composed of a fibrous horny 

 substance, with interstratified calcareous particles. The latter is most aljundant towards 

 the ba.se, less so towards the ends of the stem, branches, and twigs, the terminal twigs being- 

 horny. The surface of the axis and branches is smooth ami shining, and often exhibits 

 a golden or iridescent appearance. The ccenenchyma is in most cases very thin. The 

 polyps are large, often of greater diameter than the branch on which they are seated, 

 and usually occur in a single row on the stem and Ijranches. Their structure is simple ; 

 calyx, oesophageal, and tentacular portions are never well differentiated. A layer of 

 calcareous .spicules extends from the base of the polyp to the tips of the tentacles, leaving 

 only the pinnae free. When at rest the tentacles are simply folded over the oral disc. 

 Besides the tentacle-bearing polyps (autozooids), very small conical .shaped polvps (.-iphono- 

 zooids) occur in many species. These exhibit a capitate apex filled with nematocysts, and 

 under this the cleft-like oral cavity. The canalicular system consi.sts of four longitudinal 

 canals, which extend along the axis, and directly receive the eight canals issuing from each 

 polyp form. Thi- spicules in the ccenenchyma and pol\-ps are simple smooth noodles, or 

 .spindles, or scales which are often dentate at thoir ra;irgin and liave a hyalino a}ipoaranoc. 



The first described genus of this ftimily was HernplrUa. Steonstrup ; those which 

 Duchassaing and Michelotti^ described under the titles Clu-ijsorjorfjkt and R 



' Meiiioire sur le^ Coral, de- Antille-, 1860, Suppl.. p. 21, pi. iv. fiq. 5. 



■{'fi 



