382 THE GORGONIANS OF THE BRAZILIAN COAST. 



with small spinose or foliated clubs in the external layer and with larger, simple 

 spindles in the deeper layers. 



For descriptions and figures of most of the genera above named, with good 

 figures of their spicules, see Verrill, Trans. Conn. Acad. Sci., vol. XII, pp. 302- 

 315, 1870, with plates. 1 



PLEXAURA Lamouroux, Polyp. Flex., pp. 448-451, 1816. 



The generic type should be taken as the common West Indian species, P. 

 homomalla, by elimination. 



Seven species were given by Lamouroux. The first three now belong to 

 Plexaurella; the fourth is indeterminable ; the fifth is Suberogorgia suberosa; the 

 sixth is P. homomalla: the seventh, P. olivacea, is imperfectly known. 



Subfamily PLEX AURELLI N^B Verrill, nov. 



PLEXAURELLA Kolli ker. 



Plexaurella Kolliker, Icones Histiolog., II, p. 138, 1865. Wright and Studer, op. cit., 1869, 

 p. 140. Verrill, The Bermuda Islands, Part V, Trans. Conn. Acad. Sci., vol. XII, p. 310 



[p. 266], 1907. 



Plexauridse having a thick, porous or subcancellate ccenenchyma, everywhere 

 between the tubules, supported by relatively small warted spicules, consisting 

 mostly of spindles, double-spindles, crosses, and unevenly twinned forms; with 

 some small, short, double-heads and double-rosettes, especially in the denser 

 surface layer. Axis more or less calcareous, the calcium carbonate in strands. 

 Tentacles wholly retractile. Calicles usually immersed or only slightly raised, 

 sometimes prominent, often bilabiate. 



In transverse and longitudinal sections the ccenenchyma is seen to be per- 

 meated by small, anastomosing canals or tubules, running in all directions, some 

 connecting with the polyp-cavities, others with the exterior by small pores. 

 Between their walls the small supporting spicules are abundant and irregularly 

 placed. See Plate XXXV, figs. 12-15. 



The minute external pores of this network of tubules terminate in small 

 pits and probably function as siphonozooids, to regulate the supply of water 

 in the tubules, allowing it to escape freely during the powerful contraction of the 

 large polyps. Probably the thickness of the ccenenchyma can be made much 

 greater in life by the water entering the tubules and causing turgescence of the 

 tissues, while the polyps are expanded. 



In the related Oriental genus, Astrogorgia V. (A. sinensis), similar pores exist, 

 of larger size and more specialized, each being surrounded by a rosette of sma 



unfortunate error of the Drinter in makinz ur> the Dlates of the work cited 



'» 



representing the spicules of four species, were transposed. Therefore the explanation of the p 



XXXVa 



should be XXX VIb, fig. 3; XXXVIa, fig. 4, should be XXXVa, fig. 4; XXXVIb, fig. 3, "J 01 ^ 

 XXXVIa, fig. 3. Corresponding references to these figures should be changed in the text, ^ 

 Plexaura flavida, p. 305 ; Pseudoplexaura crassa, p. 307 ; and Euniceopsis grandis, p. 373 ; and 

 p. 305. 



