92 DISCOVERY REPORTS 



eudoxids. The irregularly triangular shape of the gonophore in transverse section is due to the fact 

 that it fits into a space between the gastrozooid and two lobes of the bract. There is no special swimming 

 nectophore in the eudoxid, and no sign of vestigial tentacles on the edge of the nectosac of either the 

 polygastric or eudoxid stage. Bigelow & Sears (1937) say that the location of the point of attachment 

 of the pedicular ('stalk') canal of the 'inferior (older)' nectophores is characteristically much closer 

 to the apex of the bell in R. plicata than in R. cymbiformis. I have not been able to confirm or refute 

 this statement. But their fig. 9 shows a connected pair of first and second definitive nectophores that 

 have been twisted back into their proper relative positions after fixation, and some tearing of tissue 

 may possibly have taken place. It is not always easy to distinguish the ' stalk ' canal from folds of the 

 muscular lamella. What Bigelow & Sears call the 'inferior' ('older') nectophore appears to me to be 

 the second definitive and therefore younger nectophore. The location of the point of attachment of 

 the stalk-canal of the first definitive nectophore is just above the angular bend in the dorsal wall of the 

 hydroecium, and not opposite the pedicular canal of the nectosac as figs. 9 and 12 of Bigelow & Sears 

 seem to indicate. The eggs, which may number up to six, measure about 1-4 x 1-75 mm. 



Hitherto unrecorded closing-net and upper-layer catches are listed on pp. 93 and 94. Only about 

 16% of the nets of these stations have been examined. 



The depth at which the greatest number (23) of the seventy-seven 'Discovery' closing-nets took 

 the polygastric stage of Rosacea plicata was about 300 m. The upper water-layers down to about 

 300 m. were fished at these stations three times as frequently (358) as the deeper water-masses (115), 

 but only 16% of this total number of catches have been examined so far. At 'Discovery II ' Station 

 1581, off the East Coast of Africa, the species was living in water at a temperature of 12-20 C. and 

 salinity 34-88-35-26 % at a depth of 50-0 m. At the Antarctic Ice Edge, Station 1639, where it also 

 occurs, the temperature was about o-i8-i-36° C. at 2400-1 150 m., and the salinity 34-68-34-74 % — 

 a fairly wide range. On 28 June 1951 'Scotia' took a first definitive nectophore and two larvae in 

 a closing-net between 1000 and 250 m. to the west of Ireland. This is the most northerly record for 

 the species, which was also taken by H.M.S. 'Research' in 1900 in the Bay of Biscay, 300-0 m. and 

 recorded as Hippopodius hippopus. 



Amphicaryon Chun, 1888 a 



Nomenclature. It seems to be quite clear from a study of the original wrappers of the journals 

 in which the generic names were published that Mitrophyes Haeckel dates from 29 May 1888, and 

 Amphicaryon Chun from 15 November 1888. But since Amphicaryon has been in common use since 

 191 1, it will be better to have the name entered in the list of nomina conservanda than to replace it 

 by the little known Mitrophyes. 



Bigelow (1911ft) defines the genus as ' Prayidae with two nectophores of very unequal size, the older 

 one degenerating. . .'. He adds that though we should expect the smaller enclosed nectophore of 

 Amphicaryon acaule to be the younger, its relatively larger size in younger stages, when it overlaps the 

 nectophore, which later encloses it, and its subsequent relative degeneration, shows that it is in reality 

 the older, and that the younger overtakes it by its much more rapid growth. I believe that the vestigial 

 nectophore is the younger, because in Prayids the buds of successive nectophores first appear inside 

 the hydroecium of the older. No one has hitherto recorded the larval stages of A. acaule, but a 

 series of three larvae of A. acaule mentioned (p. 95) shows that the larval nectophore is retained as 

 the functional, adult one, and that the reduced, shield-shaped nectophore arises as a bud inside its 

 hydroecium. I recognize three species of Amphicaryon, and am taking this opportunity to publish 

 a new generic name Maresearsia 1 for a giant new Amphicaryonine from the Atlantic Ocean (see p. 97). 

 It has recently been identified by me in the Indian Ocean too. 



1 Named after Dr Mary Sears. 



