202 



ACTINIARIA 



Verrill (1. c.) wishes to substitute the name dubia for lincolata, as he considers it questionable, if the 

 species, described by Me. Murrich, is identical with Dana's species lineolata. Also Me. Murrich (1904 

 p. 247) is a little uncertain about the identification of his species with lineolata. Verrill suggests that the 

 species is a Sagartiid, which "had lost its acontia." As far as I can understand, there is no reason for such 

 a supposition. 



Pycnanthus laevis n. sp. 



PI. 3. Figs. 4, 5. 



Diagnosis: Body in contracted state usually disc-like. Column rather thick, in contracted state 

 sometimes with indistinct longitudinal furrows in the upper part. Sphincter strong, longitudinally stratified. 

 Tentacles usually conical or seldom more cylindrical, according to the state of contraction, 96 in five cycles. 

 Outer tentacles at the base, on the abaxial side thickened and without longitudinal muscles. Pairs of mesen- 

 teries about 96, the first, second, and one part of the third cycle perfect. Some pairs of the third cycle un- 

 equally developed, consisting of a perfect and an imperfect mesentery. Mesenteries of the last cycle, only 

 in the most proximal part of the body, very small, without filaments. Parietobasilar muscles rather well 

 developed. Typical nematocysts in the ectoderm of the tentacles numerous, 22 X 2 31 X 2,5^, in the 

 actinopharynx numerous, 25 X 2 31 X 2,5 p. Spirocysts in the tentacles very numerous, from 7 X i to 

 41 X 4,5 ft. Nematocysts with discernible basal part to the spiral thread in the ectoderm of the tentacles 

 3136 X 33,5 ft. 



Colour in alcohol: uncoloured. 



Dimensions of the largest specimen in contracted state: diameter of the basal disc about 3 X 3,5 

 cm, height 0,6 cm. The smallest specimen was 0,7 cm broad and about 0,2 cm high. 



Occurrence: Davis Strait. 6635' N. 5638' W. 318 fms. Bottom temp. 39 (Ingolf-Exp. St. 32) 



many spec, on stones. 



W. of Faroe Isl. 6i3i' N. n36' W. 720 fms. Bottom temp. 24 (Ingolf-Exp. St. 46) 

 several spec. 



Exterior aspect: The pedal disc is extended and most frequently thin. The form of the body is 

 flat, almost disc-like when the animal is contracted, sometimes, as in the specimen reproduced in the fig. 5 

 PI. 3, the column forms a low cone. The surface of the column is smooth, excepting small irregular invagina- 

 tions, arisen by contraction. The uppermost part sometimes shows indistinct longitudinal furrows, and, be- 

 tween these, low ridges which are continued in the tentacles. These furrows and ridges are, however, 

 not always distinct, it is thus probable, that they have arisen by the contraction of the distal part of the body- 

 wall. The margin is distinct and not irregular. The outermost tentacles are small, arranged as palisades, 

 and a little thickened quite at the base on the abaxial side; this thickening, being probably a continuation 

 of the columnar ridges, however rapidly disappears. Me. Murrich declares that the tentacles of the genus 

 are not swollen at the base. As far as I can understand from Me. Murrich's description of Pycnanthus 

 maliformis, there may be a similar thickening as in P. laevis at the base of the outermost tentacles. Me. 

 Murrich (1893 p. 173) namely says: "The ridges upon the upper surface of the column run to the basis of the 

 outer tentacles." The tentacles are conical, sometimes more cylindrical, according to the contraction. The 



