_(3 ■ PENNATULIDA. 



nil 



mediately above it (comp. fig. 39); accordingly, the remaining part of the stalk must be regarded as 

 corresponding to the rhachis of other Pennatulids. This part decreases regularly in thickness upwards 

 — tlie middle thickness is ca. 0.448™- - until ca. 8.5-" from the mouth of the end-polyp it rather 

 suddenly tapers to a thin part - only o.24°>» broad, - which again widens quite evenly up- 

 wards and extends to the body of the primary polyp. The calcareous axis shines distincth- through 

 the thin sarcosoma, and shows the characteristic quadrangular form, with rather deeply concave surfaces 

 and ridge-like projecting edges; at the transition to the thinner part of the stalk it narrows abruptly; 

 from this point, where the diameter is aiga-"™, it continues quite thin up through the dorsal part 

 of the polyp-body, and ends in a rather curiously shaped double curve. The polyp, unfortunately, is 

 somewhat damaged, some of the anus being broken off, and the preserved arms are twisted together 

 and even rather damaged; they are longer than the polyp-body; pinnules of different sizes alternate 

 without any order. The polyp is somewhat curved in a halfmoon-shaped way and compressed late- 

 rally; reckoned from the mouth to the polyp-bud on the left side it is ca. 4™'" long; the dorso-ventral 

 diameter of the part in front of the calcareous axis is somewhat more than i™". The mouth is di- 

 stinctly oval with long axis dorso-ventral, and placed on a low oral cone very sharply divided into 

 eight lips, each corresponding to an arm and gastric cavity; eight distinct lines corresponding to the 

 edges of the eight septa, run down the polyp-body, and disappear at its hinder end; the much folded, 

 dark-pigmented phar\ngeal sac is seen faintly through the wall of the body, and below this the six 

 much twisted gastric filaments on the ventral and lateral septa. By a suitable clearing (in glycerine 

 or bergamot) these filaments are seen suddenly to cease in the lower part of the gastric cavity, where 

 their septa may still be traced for a short distance corresponding to the part which carries the sexual 

 organs in developed colonies; of such organs no trace is seen; the lower end of the two dorsal septa 

 which are turned towards tlie calcareous axis may also be seen; farther upwards they are hidden by 

 the twisted filaments of the other septa. 



On the left .side of this primary polyp, immediately below the place where the septa cease, is 

 a rudiment of a polyp Nr. 2 (p, fig. 38). This rudiment projects only quite slightly as a low truncate 

 cone with a cleft-like oral aperture; the eight septa with their filaments are distinctly begun, but no 

 trace of arms is seen. The length of this rudiment is 0.32™'", the breadth 0.154™'". 



Along the primary polyp's dorsal side, which is distended by the calcareous axis, is a row of 

 zooids (z) on each side, all placed in the usual way, i. e. with the dorsal side toward the apex of the 

 axis. No terminal zooid is seen above the end of the calcareous axis. Zooids of quite the same 

 appearance are further found down the stalk with intervals of 0.5— i""", down to ca. 2'"'" from the 

 lower end, as before mentioned (fig. 39). The zooids vary in size between 0.096 and 0.240"""; the 

 lowermost ones are generally the smallest; on the stalk they are in the main placed on the lateral 

 surfaces, the ventral side, at all events, quite wanting zooids. None of the zooids show any trace of 

 llie tentacle which the larger zooids always possess in developed Umbcllula elsewhere. 



On the lower egg-shaped end of the stalk, which represents the peduncle proper, quite small 

 oval calcareous spicules are seen under high magnifying powers and by suitable clearing (as I did 

 not wish to destroy the specimen, I had to be content willi only convincing myself of the existence 

 i>f the.se spicules); the other part is quite devoid of spicules. 



