ON A NEW SIPHONOGORGJD GENUS CACTOGORGIA. 833 



Cactogorgia expansa, n. sp. (figs. 7, 8, 9a, 96, 9c). 



Of this species there is but a single specimen, of a pale chocolate colour ; it is 

 35 millims. in height and 30 millims. in maximum breadth. It has a somewhat 

 cylindrical stem surmounted by two fan-shaped polyp-bearing lobes, which give it a reni- 

 form appearance (fig. 8). The sterile stem is 19 millims. in height and 7 millims. in 

 diameter ; the lobes are respectively (1)16 millims. in breadth, 1 1 millims. in height, with 

 a width of 11 millims. at the constriction ; and (2) 18 millims. in breadth, 14 millims. in 

 height, with a width of 13 millims. at the constriction. One of the lobes, owing to a 

 downward growth, has become slightly convoluted. This species resembles C. celosioides, 

 n. sp., in general character, but the general tone is more opaque. 



The polyps, as in the first species, occur mainly on the periphery, but this feature 

 is not so marked ; several arise on the flattened portion from points in close proximity 

 to the circumference. The stalk is quite destitute of polyps. 



Several canals penetrate the stem ; these have very thin walls, but maintain their 

 cylindrical form by reason of the rigidity of the coenenchyma. They branch in the 

 polyp-bearing part, and separate canals may be traced to the individual polyps. 



The coenenchyma is densely spiculose. The spicules on the surface are opaque and 

 appear white ; they are arranged in a very irregular manner, so that they present a 

 peculiar and characteristic appearance quite distinct from that in C. celosioides, n. sp. 



The verrucse are not very conspicuous ; they are supported by spicules arranged for 

 the most part longitudinally, but often quite irregularly. The anthocodise (fig. 7) are 

 about 1'5 millims. in length and 1 millim. in breadth when partially extruded. They 

 bear a distinct "crown and points" arrangement. The "crown" consists of about 

 8 rows of curved spicules interlocking more closely in the upper portion of the stomodceal 

 region. Surmounting this are eight points composed of 6-8 pairs of slightly curved or 

 club-shaped spindles arranged " en chevron " ; these increase in size towards the base of 

 the tentacles. On the aboral surface of the tentacles there are numerous small scale-like 

 spicules arranged longitudinally. 



The spicules are predominantly spindles ; the following are some of the measurements 

 of their length and breadth in millimetres : — 



A. Stalk : — opaque yellowish multituberculated spindles— straight and curved — 



1-5x0-3; 1-4x0-25; 11 x 0'2 (fig. 9a). 



B. Anthocodise — 



(1) "Crown and points" — slightly opaque or translucent tuberculated spindles 



and clubs— 0-8 x O'l ; 075 x 0-08 ; 07 x 0*075 (fig. 9b). 



(2) Tentacles — pale yellow, transparent scales — 0'08x0'02; 0-06x0*02; 



0-04x0-015 (fig. 9c). 



Locality. — Off Cape Comorin, 38 fathoms. 



