20 



Stat. 177". Lat. 2° 30' S., Long. 129° 28' E. Cat. 95 D. ale. i^O°\^. 7 specimens. 



Stat. 184. Anchorage off Kampong Kelang, South-coast of Manipa-island. Cat. 142 B. ale. 90° g. 



2 specimens. 

 Stat. 185. Lat. 3°2o'S., Long. I27°22'.9E. Cat. 100 B. formald. 4°/^. One specimen. 

 Stat. 189'. Lat. 2°22'S., Long. I26°46'E. Cat. 65 D.G. formald. 47o- ~ specimens and Cat. 



127 F.A. ale. 90%. 8 specimens. 

 Stat. 194. Lat. i°53'.5S., Long. I26°39'E. Cat. 23 A. C. formald. 4°/^. One specimen. 

 Stat. 203. Lat. 3°32'.5S., Long. 124° 15'.$ E. Cat. 126B. ale. 9o7o- 8 specimens. 

 Stat. 205. Lohio-bay, Buton-strait. Cat. 50 C.C. ale. 9o7o- 5 specimens. 

 Stat. 243. Lat. 4°3o'.2S., Long. i29°25'E. Cat. 134. ale. 9o7o- 0"^ specimen. 

 Stat. 245. Lat. 4° i6'.5 S., Long. I30°I5'.8E. Cat. 143 F. ale. 9o7o- 7 specimens. 

 Stat. 315. Anchorage East of SailusBesar, Paternoster-islands. Cat.\2(^(L. ale. 90°/^. One specimen. 



The SIboga expedition has brought together a most splendid collection of Abyla pentagona 

 (33 complete specimens, 98 loose superior nectophores, 79 loose inferior nectophores), one of 

 the Calycophorids which has been found in great profusion in the Atlantic Ocean and which 

 has been described by a great many authors (Koll. 54, Lkt. 53, Hkl. 88b etc.). 



From the Indian and the Pacific Ocean (south-east coast of New Guinea, Indian Ocean 

 off Timor, in the South Pacific) Huxley (59 p. 41) describes under the same name a smaller 

 specimen which he thinks identical with the Abyla pentagona of Kolliker 54, Leuckart 54, 

 Gegenbaur 60 etc. At the same time he recapitulates how Leuckart 53 describes under the 

 name of Aglaisma pentagonuitt, an exceedingly small Abyiid (8 mm.) which is to his opinion 

 identical with the Abyla pentagona of Ouoy and Gaimard and which Leuckart himself calls a 

 "unvollstandig entwickelte Abyla pentagona (53 p. 53)". Later authors as Haeckel 88b and 

 Chun 88 and 97 a think Huxley's specimens different and Haeckel even calls it Calpc huxleyi 

 (88b p. 164). 



Now the .Siboga expedition not only brought many large specimens but also a considerable 

 number of smaller ones, but we looked in vain for any other specific difference. 



In the description of Abylopsis quincunx we will give our opinion as to the position of 

 Huyley's specimen in the system. 



It was very remarkable to find such great differences in size between the respective 

 specimens. The length of the very largest Abyla pentagotia was 24 mm. (measured from the 

 superior facet of the superior nectophore to the utmost point of the proximal ridge in the 

 inferior one) of the smallest i 2 mm. (measures taken as above). We give three sketches (PI. II, 

 figg. 17, 18, 19) of the superior nectophore of Abyla pentagona, which we use in comparing 

 them with the same in Abylopsis quincunx Ch. (see p. 22). All the inferior nectophores possess 

 the characteristic course of the canals such as Gegenbaur (60 p. 354) described so well. 



The principal canal divides itself at once at the ajjex in the superior hindwall of the 

 nectophore into four canals. 



The proximal one first follows the upperwall of the nectosac, then goes straight down, 

 ending below in an enlargement. The distal canal follows the hindwall of the nectosac and 

 shows the same enlargement near the velum. But it does not end there, but gives off a short 

 canal, the course of which is proximal to the left and this short canal ('/o of the length of the 

 main posterior one) ends also in a club-shaped enlargement. The right lateral canal follows the 



