300 Sou then I (ross. 



thcsL' pit-likf (Impressions, each coiitaiuiug an embryo and involving 

 at first only an invagination of the ectoderm into a hollow in the 

 niesogkea, may be gradually enlarged, by the growth of the embryo 

 carrying tiie body-wall inwards, invaginating all three layers — the 

 ectoderm, mesogkea and endoderm, and forming cavities lying 

 completely within the column. He gives a figure (1 p. 237) 

 showing a section through such a chamber containing an emljryo, 

 measuring from 1 to 1*5 mm. in diameter, and illustrates the 

 condition of the invaginated ectoderm, mesoglcea and endoderm 

 forming the wall of the cavity. The figure also sliows the opening 

 to the exterior, and that the chamber is completely separated from the 

 cielenteron. In the general relation of the wall-layers this chamber 

 greatly resembles the brood chambers, about to be described, of the two 

 species from the Antarctic, but is of very much smaller dimensions. 



Professor Verrill's specimens do not appear to exhibit this further 

 development of the ectodermal pits into sac-like invaginations of the 

 whole body-wall, involving all three layers, such as Carlgren describes, 

 although the external appearance of the specimens figured by each 

 author are very similar and certainly suggest the same structures. 



Dr. Kwietniewski in 1898 (5 p. 121) mentions that a new 

 species of Leitealia from Spitzbergen, which he describes, possesses 

 a similar " Brutraum " in the body-wall, containing a developing 

 embryo, but differing from the species described by Carlgren in 

 1893, in having it placed immediately below the parapet in the 

 upper part of the column instead of on the lower portion. 



In 1899 Dr. Carlgren (2 p. 14) gave some further particulars, 

 but no figures, of " Brutraumen " found in Condylactis fjconjiana 

 from the collection of the German South Polar Expedition of 

 1882-83, which he says are of similar character to those he described 

 in a Tcalia in 1893 (1 p. 234). They extend generally over the 

 whole body-wall, are numerous, and contain from one to three 

 embryos. Such then is a brief account of the literature ' on brood 

 chambers distinct from the coelenteron, in Actinians. 



' Dr. Carlgren, iu :i quite recent i)aper, ijublished in August, lilOl ('la \\ 468), 

 gives additional jiarticularB and figures of the specimens mentioned in liis"Vor- 

 liiufige Mittcilung" (1 p. 231), published iu 1893. lie here describes these 

 specimens under the names of Actinostola sibirica and Epiadis niarsitpialis, botli 

 new species. In additicm he describes a new genus of Paractid under the name of 

 Mnrsupifcr Vahlivins, which ]K)ssesscssix brood pouches arranged radially, and 0]icning 

 by separate aiKjrtures on the body-wall about two-thirds the height ot the culumn 

 lri)m tlie foot-disc. lOach brood chamber contains a large number of embryos, the 

 smallest about tliirty and the largest ab<jut one hundred. An important character 

 of this new genus Marsujn/er is the presence of two sphincter muscles, one placed 

 about the normal iKtsition, and the other just above tl)e openings of the brood pouches. 



