HYDROIDA II 



23 



The single gonothecse are reversed, narrowly conical to almost cylindrical, fastened to the hydrocaulus 

 by a rudimentary stalk at the narrow end; distally, they are furnished with three, more rarely with four 

 or two, round lateral openings, each with a short neck. 



Material: 



"Ingolf" St. 7 63°i3' N., i5°4i' W., depth 600 fathoms 4,5° 



- 25 6 3 ° 3 o' N, 54 °25' W., - 582 - 3,3° 



- - 81 6i°44' N., 27°oo' W., — 485 — 6,i° 



"Thor" 6i°i 5 ' N., 9 °33' W., — 872 metres 



Levinsen (1913 p. 287) believes to have found a blind sack in Lictorella pinnata\ this must 

 doubtless be due to an accidental S-shaped curvature of the polyp, which would not, however, produce 



600 m 



2000 m. 



Fig. VII. Finds of Lictorella pinnata in the Northern Atlantic. 



a blind sack of any real anatomical importance. Microtome sections reveal an entirely uniform gastral 

 endoderm, and I have not been able to find any portion of the endoderm histologically corresponding to 

 the epithelium in the blind sack of Sertulariida?. The "blind sack" observed must thus be due to accident. 

 Lictorella pinnata exhibits a highly remarkable distribution (fig. VII). It belongs to the 

 upper part of the abyssal region, but penetrates as far down as 1300 metres; on the other hand, the 

 species can at times occur right up in the littoral region, and has been met with in the Hardanger 

 Fjord even up at a depth of only 90 metres. Horizontally, the species seems to be quite widely distri- 

 buted, but the few records from southern seas are unreliable, as the species has here been confused 

 with Lictorella anfipatlies (Lamarck). Pictet and Bedot (1900 p. 16) record it from the Bay of Gas- 



