156 MR. R. KIREPATRIOK ON THU 



presence of the peculiar glands supposed to be i-enal, one on each 

 side of the posterior end of the endostyle. In 1903 Hartmeyer 

 described a second new species, R. ritteri, from Baffin Bay, 

 20 fms. ; the new species differed in having fewer inner longi- 

 tudinal vessels, and in having accessory gill-clefts supposed to be 

 absent in Ritter's species. Hartmeyer showed that the paired 

 glands were not renal, but organs for supplying a secretion for 

 fixing the animal to the bottom; the true renal organ was found 

 by him to be a minute oblong body placed below the stomach. 



In 1907-8 Hedikorzev described two more new species, B. gi- 

 gantea from Kotelnyi Id. and New Siberiaia Ids., 3-9 metres ; 

 and E. warpacliovskii from Nova Zembla, 40 metres. 



In 1908 Michaelsen added a further new species R. intermedia, 

 based on some specimens found in the Hamburg Museum, and 

 from an uncertain locality. 



In 1911 Huntsman* made the interesting discovery that in 

 1776 Pallas t had described an undoubted Rhizomolgula, viz. 

 Ascidia i/lobularis from Kara Sea, and he identifies some speci- 

 mens from Herschel Id., Canadian Arctic Ocean, with this 

 species. 



Lastly in 1916, RedikorzevJ arrived at the conclusion that 

 all the forms hitherto described belonged to one species, Ascidia 

 glohularis Pallas, the supposed specific differences being merely 

 variations such as might be found in a large number of specimens 

 from any particular locality ; or, again, that certain variations in 

 external appearance (especially as regards the peduncle) might be 

 due to methods of collection and preservation. 



The writer adopts Redikorzev's view with the reservation that 

 a more detailed study of the oral tentacles might show genuine 

 specific differences. The number of primary tentacles might be 

 regarded as a specific character, but not the number of multiples 

 of the primary number. 



The specimens from Spitsbergen have eight primaries ; but 

 there appears to be some uncertainty concerning the number 

 of primaries in the other supposed species \^R. arenaria, 12-14 

 tentacles ; R. 7'itteri, 12 large ones, also with smaller (about 18 in 

 all); R. warpachovskii, 12; R. gigantea, 18 in three sizes; R. inter- 

 media, 40 in three orders]. 



Distribution. Pallas's original Ascidia glohularis was gathered 

 in 1770 fi'om Kara Bay, Kara Sea. Over 130 years later the 

 same species (named R. warpachovskii Rdkrzv.) was got from 

 Matochkin Strait, Nova Zembla, practically the same locality ; 

 for Nova Zembla curves round Kara Sea like a sickle separated 

 from the mainland only by another island. The species is 

 recorded also from New Siberia and from two American Arctic 



* Tvans. Canadian Inst. 1911-21, ix. p. 127; also Contrib. Canadian Biology, 

 Ottawa, 1912, p. 136. 



t Reise, 1776, iii. p. 709, Appendix ; and Nova Acta Acad. Petropol. 1787, ii. p. 247, 

 Tab. vii. figs. 39, 40. 



X Faune de la Russie et des pays limitrophes, 1916. Tunicata, livr. i. pp. 126-137. 



