138 BULLETIN 82, UNITED STATES NATIONAL MUSEUM VOLUME 1 



still l^'ing in their original positions on tho right and left side of the cinbrj-o, the mesentery 

 between them being in the posterior mid-line. 



While in the course of normal development the egg undergoes total and regular 

 cleavage, a curious abnormal mode of development was only too commonly observed 

 in the cultures, the nuclei only, Ij'ing free in the egg substance which docs not show any 

 indication of cell limits, dividing, thus forming a syncytium. Quite a number of nuclei 

 may be found lying in a fairlj' regular laj'cr near the surface, and in the later stages also 

 some in the inner part of the egg. The development does not proceed further. 



Mortensen believes there can be no doubt but that this abnormal development 

 is due to the unnatural conditions in the aquaria, probably to the high temperature. 



A fairly complete series of tlie post-larval stages was obtained by examining the 

 material dredged in the localities where tlie adults were common. They were found 

 attached especially to hydroids, but also to polyzoans, worm tubes, and other objects. 



A careful study of these revealed the presence of infrabasals, three in number, 

 small and of equal size, forming a small ring lying wholly within the basals so that it is 

 impossible to detect it on entire specimens. 



Localities. —Thor station 171; south of western Iceland (lat. 63° 15' N., long. 

 22° 23' W.); 216-326 meters; 1903 (1, CM.). 



Triton station 3; Faroe Banks (lat. 60° 39' 30" N., long. 9° 06' W.); 159 meters; 

 temperature 9.44° C; sand and shells; August 8, 1882 [P. H. Carpenter, 1884, 1888; von 

 Graff, 1SS4; Bell, 1893]. 



Faroe Islands; 16 kilometers east by south from Nols0 (south point); about 146 

 meters; Th. Mortensen, June 20, 1899 [Lieberkind, 1929] (1, CM.). 



Faroe Islands; 101-183 meters (1, CM.). 



Scandinavia [Forbes, 1841]. 



Norway [Forbes, 1841; A. H. Clark, 1912, 1913] (10, B.M.; CM.; Berl. M 1039; 

 H.M.). 



Beian, at the entrance to Trondhjemsfjord (1, K.M.). 



Trondhjemsfjord [M. Sars, 1861; A. H. Clark, 1912] (several, K.M.; Berl. M., 

 2887). Outer part of Trondhjemsfjord, from Galgenesset; 40-100 meters [Storm, 

 1878, 1879]. 



Aun0, Hitteren, at the entrance to Trondhjemsfjord [M. Sars, 1861]. 



Aure, between Trondlijcm and Ivristiansund (l. Berg. M.). 



Four miles north of Kristiansund; 27-36 meters (1, Berg. M.). 



Ivristiansund, 91-128 meters [M. Sars, 1861] (several, K.M.). ' 



Veblungsnes, Romsdalen [Nansen, 1885]. 



Storeggen (edge of the continental shelf, off Aalesund) (1, K.M.). 



Vaagsfjord, leading out of the Nordfjord; 55-274 meters [Grieg, 1897]. 



Brj-ggen, Nordfjord (Berg.M.; courtesy of Dr. Grieg). 



S0ndfjord [Diiben and Koren, 1846; Grieg, 1896] (6, Berg.M.). Askevold, S0nd- 

 Jord (1, Berg. M.). Flor0, S0ndfjord [Nansen, 1885; A. H. Clark, 1912] (fragment, 

 Berl. M., 1043). j v o . 



Sogncfjord [Grieg, 1896]. Hus0, at the entrance to Sognefjord [Danielssen, 1892; 

 Grieg, 1912]. 



Alichael Sars; west of Sognefjord (lat. 60°55' N., long. 8°56' E)- 1-^6 meters- 

 temperature 9.33° C; August 14, 1902 (1, CM.). ' ' 

 Mangerfjord [Grieg, 1896]. 



