91 



Thesioides inermis, n. g. ct sp. Plate VI. figs. I find 2. 

 General Featuri-*. 



This new type is marked by the greatly elongated slender rachis borne by a 

 short stalk. 



The autozooids are long, slender, and without calyces. They are not fused 

 to form pinnules, but occur irregularly on the pararachidial sui-fan 



The rachis is more or less quadrilateral, with grooves on the metarachidial and 

 prorachidial surfaces, distinct on the lower part, less distinct in the upper part. 

 There are no spicules. 



This genus must be placed in the first section of the Junciformes of Kolliker, 

 near the genus Bathyptilum. We have named it Thesioides from its resemblance 

 to the raceme of Thesium. 



More detailed Description. 



The maximum length is 360 mm. 



The short stalk shows a terminal enlargement in which the base of the axis 

 lies, and another a short distance above this. The colour of the stalk is yellowish 

 to pinkish-brown ; the autozooids are brownish-white in their lower part, darker 

 brown in their upper part and tentacles. There is a peculiar bluish tint all 

 over. 



The axis is quadrilateral ; its sides show shallow grooves which become less 

 distinct towards the upper end. The lower portion is reduced very rapidly, 

 lies curved into a hook in the lower swelling of the stalk ; the upper portion tapers 

 more gradually towards the tip, where it becomes filamentous. 



The rachis is long and slender, more or less quadrilateral in cross section, and 

 bears the autozooids irregularly on the pararachidial surfaces. 



The autozooids vary in length from 2 '5- 10 mm. The longest have a 

 diameter of 1 '3-1 '4 mm. They are probably cylindrical in shape, but they are 

 greatly wrinkled owing to contraction in the preserving fluid. The tentacles are 

 short, and bear on each lateral surface one row of pinnules, which, owing to crowd- 

 ing, seem to be arranged in two rows at the base. The tentacles themselves arc 

 very peculiar in shape, and may be divided into two parts ; the lower part short 

 and broad with the pinnules arranged as above, the upper part a little longer, thin 

 and whip-like, with very few long flagella-like pinnules rising from it. On the 

 lower part a number of the pinnules near the tip are also produced into long 

 flagellum-like structures. This arrangement must have given the tentacles a 

 peculiar appearance in the living state. 



Siphonozooids are present on the pararachidial surfaces between the auto- 

 zooids, and also form a row along each edge of the grooves on the prorachidial 

 and metarachidial surfaces. 



