368 DISCOVERY REPORTS 



possession of an ornament round the neck which d'Orbigny either failed to notice or 

 could not see with the magnifications at his disposal. They agree with a form which is 

 very generally distributed in the Falkland area, indeed often the commonest species of 

 Lagena . 



D'Orbigny's figure and the subsequent figures of Reuss (R. 1862, FFL, p. 329, 

 pi. iv, fig. 53 ; R. 1863, FCA, p. 144, pi. i, fig. 15) must therefore be discarded as mis- 

 leading representations of the type which he intended to figure, and d'Orbigny's 

 original description of L. vilordeboana "ovale, tres renflee, arrondie en arriere, un peu 

 acuminee en avant, ornee en long de vingt a vingt-sept cotes saillantes tres prononcees; 

 ouverture ronde, placee a I'extremite d'un prolongement mediocre. Couleur blanc 

 uniforme " will require to be supplemented with the words " the costae merge round the 

 neck and form a solid collar of shell substance which is covered with fine pitted depres- 

 sions". We figure some typical specimens. 



These depressions on the collar mark the very close affinity of d'Orbigny's species to 

 L. ivilliamsoni (Alcock). The two forms differ indeed only in the greater number of 

 costae and the greater number and much smaller size of the depressions in the Falkland 

 form. As the older species, L. vilardeboana must become the type of the costate Lagenae 

 with hexagonal neck ornament, and L. williamsoni must be regarded as a more strongly 

 marked variety of it. 



L. vilardeboana is widely distributed in the area and very often abundant. The best 

 stations are WS 88, 90, 92, 93, 245. The species is very variable in the number and 

 acuteness of the costae, and at several stations, notably WS 93, there is a complete 

 gradation between L . vilardeboana and L . williamsoni. On the other hand , there are several 

 stations at which it occurs to the exclusion of L. williamsoni. 



Average length, 0-40 mm.; breadth 0-22 mm. 



192. Lagena williamsoni (Alcock) {non Harvey and Bailey). 



[note. In 1853, W. H. Harvey and J. W. Bailey published a description in Latin [Pioc. A. Nai. Set. 

 Philadelphia, v. (1854), p. 431) of an organism under the name of Lagena williamsoni, which is clearly 

 a Nodosaria, species problematical, but possibly scalaris (Batsch). We do not propose to interfere with 

 the use of a name, which has been universally used for over half a century in favour of an incorrect 

 diagnosis unaccompanied by any figure.] 



Entosolenia ivilliamsoni, Alcock, 1865, NHC, p. 195. 



Lagena williamsoni, Wright, 1877, RFDA, p. 104, pi. iv, fig. 14. 



Lagena williamsoni, Cushman, Stewart and Stewart, 1930, TFNC, p. 59, pi. viii, fig. 5. 



Fourteen stations: 48, 51 ; WS 76, 80, 83, 89, 92, 93, 97, 99, 210, 217, 225, 248. 



This very common British type, characterized by a pyriform shell which is decorated 

 with 12-18 well-marked costae, merging into a collar of hexagonal ornament round the 

 neck, is well distributed in the Falkland area, though never so abundant as L. vilarde- 

 boana (d'Orbigny). The best specimens were recorded at WS 217, 248, where it was the 

 only type and at WS 92, 93, where the two forms occurred together with intermediate 

 links. 



