86 



Locality : Station 239 ; 11' 49' 30" N., 92° 55' E. ; 55 fathoms. 



There is only one other recorded species of this genus, viz. Protocaulon 

 mollc, Kolliker. The genus has a noteworthy geographical distribution from 

 the "Challenger" Station 169, north-east of New Zealand, 37' 34' S., 179° 22' E., 

 to the Andamaus. Its bathymetrical range is no less interesting, varying from 

 55 fiithoms in the present case to 700 fathoms for Protocaulon molle. 



Family Protoptilid.e. 



Protoptilum medium, n. sp. 

 DistichoptUum graciJe, Verrill. 



Protoptilum medium, n. sp. Plate III. fig. 1. 



This species is represented by an incomplete specimen 133 mm. in length. 



At the basal end there is a small globular swelling, tlie walls of which are very 

 thin ; above that there is a longer spindle-shaped swelling. At the upper end of 

 the latter two grooves start, one running up the proracliidial surface, the other 

 running up the opposite side. The prorachidial groove is more marked, and 

 extends the whole length of the rachis ; the other is not so evident, and gradually 

 disappears. 



The axis is cylindrical, smooth, brittle, and very calcareous. The superficial 

 spicules of the coenenchyma give the specimen a granular appearance. 



At the lower end of the rachis the immature autozooids appear as one row on 

 each lateral surface, those in the one row alternating with those in the other. As 

 they reach maturity they gradually depart from the strictly lateral position, and 

 become more dorso-lateral. The mature autozooids are closely appressed to the 

 stem, 4 "5-5 "5 mm. in length from origin to apex, with an oral diameter of 

 2 "5 mm. They are abruptly truncated at the upper end, but have no teeth. The 

 tentacles have a few projecting spicules at their proximal end, and are capable of 

 com2:tlete retraction, forming an eight-rayed star. 



The spicules of the coenenchyma are spindles or rods free from warts or spines, 

 but ribbed. They are colourless and very translucent. 



This species seems to be intermediate between P. aherrans (Kcilliker) and P. 

 carpenteri (Kolliker). 



Locality: Station 151; Colombo Lighthouse, S. 64, E. 131 m. ; 142-400 

 fatlioms. 



