Indian Deep-sea Dredging. 5 



expanded colony forms a smooth mass of a cartilaginous con- 

 istence. No trace is to be detected of any spiral shell which 

 might have formed a basis of investment for the polyps. 



Order M A D RE POK ARI A. 



Only four species of deep-sea corals were taken during the 

 season, but all on different occasions. Two of them appear 

 to be new to science, and are here described. We take this 

 opportunity of describing also a remarkable specimen of a 

 (deep-sea) Ehizotrochus from the neighbourhood of Gaspar 

 Straits, lately presented to the Indian Museum by Captain 

 Worsley. 



Madeepoeaeia Apobosa. 



Family Turtinolidae. 



[Rhizotrochus, Edw. & H. 



1. Rhizotrochus Worsleyi^ sp. n., Alcock. 



Corallum translucent, extremely thin and fragile, low, 

 moderately compressed, cornute, terminating abruptly in a 

 small, curved, laterally-situated pedicle, the longitudinal axis 

 of which meets the same axis of the calicle at an angle of 

 about 125°. From the thecal wall, which is almost smooth 

 with but faint and incomplete costal striations, branch out 

 ten coarse, rudely cylindrical, hollow rootlets of unequal 

 length, which communicate directly with the calicular cavity ; 

 they are arranged in two irregularly concentric series. The 

 calicle is deep, but largely filled up by the prominent primary 

 and secondary septa ; its orifice is irregularly elliptical, and 

 its margin is everted, in places impendent, and crenulate and 

 irregularly plicated. There are six systems of septa and five 

 complete cycles ; the septa are not exsert, except where they 

 coincide with the indentations of the marginal plications ; 

 and in all the systems, except in the half-system coincident 

 with and in the half-system opposite to the laterally-situate 

 pedicle, they have a strong lateral twist towards the pedicle ; 

 their surfaces are finely and distantly granular. The primary 

 and secondary septa of the same system are coequal, but the 

 different systems are unequal with one another ; they descend 

 almost vertically, but with the lateral twist referred to, to be 

 loosely fused in the bottom of the calicle by their edges, which 

 there become sinuous, and thus to form a rudimentary parietal 

 columella ; their surfaces are transversely striated. The 



