J24 DISCOVERY REPORTS 



Nearly two-thirds of the specimens from the Antarctic are of Promachocrinus 

 kerguelensis, the largest and most common of Antarctic crinoids. The bigger of the 

 remaining species — those of the family Notocrinidae and the subfamilies Heliometrinae 

 and Isometrinae — are represented by moderate or large numbers of specimens. Of the 

 smaller species belonging to the subfamilies Zenometrinae and Bathymetrinae there are 

 only one or two specimens, often imperfect, of each, despite the numerous dredgings 

 made by the Discovery Committee's vessels. It seems probable that many more small 

 species remain undiscovered in moderate depths in Antarctic seas. 



I have included notes on the two species, Solanometra antarctica and Eiimorphometra 

 conchma, which are known to occur in the Antarctic but which are not represented in 

 the Discovery collection; and on Eiimorphometra hirstita from Marion Island. 



I have also partially redescribed from their types in the British Museum collection 

 three non-Antarctic species, Isometra lineata, I. ongustipinna and Phrixometra longipinna, 

 to which certain of the Antarctic species are related. 



How well many of the specimens are preserved may be seen by referring to the plates 

 of this report. The larger were fixed by gently inducing them while still alive into tubes 

 just wide enough to hold them, and then by adding strong spirit. 



Myzostomtim was found on Promachocrimts kerguelensis, the two species of Florometra, 

 Aiithometra adriani, Isometra flavescens and Notocrinus mortenseni. 



In the lists of stations under each species the gear in which the specimens were caught 

 is shown by means of symbols: OTL, DLH, etc. These symbols are explained in the 

 introductions to the Station Lists in this series of reports (Vol. i, pp. 3-5, 1929 ; Vol. in, 

 p. 4, 1930; Vol. IV, pp. 3-4, 1932) except for the following: DS, small dredge; DRR, 

 a large dredge bag attached to the frame of a Russel bottom net. 



I have examined the Antarctic comatulids, those collected by the National Antarctic 

 ('Discovery') Expedition, 190 1-4 and the British Antarctic (' Terra Nova ') Expedition, 

 1910, in the British Museum collection. They were reported on by Bell in 1908 and 

 1917 respectively. He recorded Antedon antarctica {= Solanometra antarctica) which 

 was not represented and did not recognize two species, Florotnetra mawsoni and Noto- 

 crinus virilis, which had not been described at that time but which were represented; 

 he gave, too, only a few of the localities at which specimens were taken. I give at the 

 end of this paper (p. 220) a complete record of the Antarctic comatulids taken by those 

 expeditions. 



The collection contains about fifty-eight pentacrinoid larvae. 



About twenty of them are of Isometra vivipara and are attached to the upturned cirri 

 of the females. The development of this species has been described by Mortensen (1920) 

 and nothing is added here. 



Clark (1921) has described a long series of pentacrinoid larvae of Promachocrinus 

 kerguelensis. There are three in the present collection (p. 200). 



The remaining larvae are of much greater interest, for they were not previously known. 

 They are described in detail (pp. 202-219). There is a series of fifteen, the youngest 



