228 ACTINIARIA 



Occurrence: East coast of N. America from New-Foundland to Cap Fear 50—640 fins, (teste 



Verrill). 

 Baffin Bay. 7i°34' N. 65°55' W. 306 fms. (Wandel 1880). Davis Strait 66°49' N. 

 56°28'W. 235 fms. (Wandel 1889). 66°35' N. 56°38' W. 318 fms. 

 Bottom temp. 3,9° (Ingolf-Exp. St. 32). Kvanefiord S. Greenland 

 420 fms. (Rink-Exp. 1902 St. 5). 

 6i°33'N. 19° W. 1089 fms. Bottom temp. 3° (Ingolf-Exp. St. 65). 

 59°28'N. 8°i' W. iioo — 1300 m. Bottom temp, at 1000 m. 8,07° (Michael Sars-Exp. 



1902 St. 76). 

 Norway. Finmark Jokel fiord 80 — 100 m. (Nordgaard). Stonnesbottn 40—80 m 



(Nordgaard). Drontheimfiord. Drobak (Carlgren). 

 Skagerrak. 230 — 430 fms. (Gunhild-Exp.) 140 m (Thor-Exp. 1903 St. 19). 

 Sweden. Kosterfiord 210 m (Arwidsson). 220 — 230 m (Sandberg 1901). Vader- 



oarne. Gullmaren 40 — 50 m (Carlgren and others.) 

 S. W. coast of Ireland. 5i°36' N. ii°57' W., 5i°35' N. ii°55' W., 5i°27' N. ii°55'W. 



540 — 720 fms. (teste Stephenson A. atrostoma). 

 Further distribution: Japan Kinshin S. off Nagasaki (Bock-Exp. 1914). 

 Exterior aspect. The exterior of this species has before been described by Verrill, by myself, 

 and by Stephenson. Some of the specimens I have examined, as those from Davis strait, Kvanefiord 

 and the station 65 (Ingolf-Exp.), were provided with rather strong tubercles over the whole surface of the 

 column, while others were tuberculated only in the upper part of the body-wall. It seems as if the specimens, 

 Uving in deeper waters, are more tuberculated than those, Uving in shoal waters, my material is, however, 

 too small for deciding this with certainty. The appearance of the tentacles also varies, in as much as all 

 tentacles may be devoid of the mesogloeal thickenings at the base of the outside, as in the specimens from 

 Gullmar-fiord, while several specimens, as those from Baffin bay and Skagerrak, have thickenings only on the 

 outer tentacles, and still others — specimens from the Ingolf-Exp. (St. 65), Michael Sars-Exp. (St. 76), Davis 

 Strait and Kosterfiord (220 — 230 m) — are provided with such thickening's on all tentacles. Also in the Ameri- 

 can forms (from Maine bay and Martha's Vineyard) I have observed specimens with and without tentacle 

 tubercles. I must, therefore, regard Stephenson's ^. flifrastoma, in the main proposed on basis of the presence 

 of tentacle tubercles, as identical with A. callosa, as the anatomical characters of atrostoma agree with those 

 of Verrill's species. I will besides add that the specimens, taken during the Michael Sars-Expedition, perfectly 

 resemble A. atrostoma. Thus, to my mind the species shows a distinct tendency to form tentacle tubercles, 

 as it seems, especially in the specimens living in deeper water 1. 



Anatomical description. The anatomy of this species has before been sufficiently described by 

 myself and by Stephenson, so that it is unnecessary to discuss it here. I will, however, give an account 

 of the size of the nematocysts and spirocysts in some specimens, a: typical nematocysts, h: large specific 

 nematocysts, c: nematocysts with discernible basal part to the spiral thread, spi: spirocysts. 



' The new genus, Catadiomene, proposed by Stephenson (1920) for the Actinostola-iorms with sweUings of the mesogloea 

 at the aboral side of the tentacles, thus must be dropped. 



