Notarchus and Heiabranchus. 7 



petersii Bergh (from Mozambique) and H. anaiteus Bergh (from 

 the New Hebrides). The nearest relative of the species is H. 

 suezensis. It is distinguished from the latter by the following 

 characteristics: 1) The general shape of the body is circular. In 

 H. suezensis it is elliptic. 2) The dorsal side — if we do not 

 consider the mantle — has its greatest breadth on the middle. 

 In H. suezensis the back part is broadest. 3) The border of the 

 mantle is more strongly developed. 4) The oral tentacles are 

 kidney-shaped. They are divided into 8 rather large lobes, all 

 of which have a shallow indentation on the middle. The ends 

 of the lobes are club-formed. H. suezensis, on the other hand, has 

 oval oral tentacles which are provided with numerous rounded 

 lobes, all of the same size. 5) The exterior laminated part of the 

 dorsal tentacles narrows gradually towards the point. In H. 

 suezensis the base of this part is thick, then it narrows quickly 

 towards the point. 6) The front part of the foot is not excavated. 

 7) The back end of the foot nearly reaches the free edge of the 

 border. In H. suezensis it does not reach farther than a little on 

 the interior edge of the mantle. 8) The gills are considerably 

 larger, more strongly built and more ramose. 9) The genital ori- 

 fice is situated about half way between the median line and the 

 interior edge of the mantle. In H. suezensis it is situated close 

 to the interior edge of the mantle. 



Bibliography of the Genus Notarchus Cuvier. 



Adams, H. and A., The Genera of recent Mollusca. Vol. -J. 8. 

 London 1858. 



N. gelatinosus Bang (vol. 2, p. S8, figured vol. 3, pi. <>0. f. 1). \. 

 cuvieri Blainv.?, N. grisetis Bisso, N. ocellatas Han*;. A". p m t tOh u 1'iui. 

 (vol. 2, p. 3G), Burmtella Lcachii Bi.ainv. (described vol. 2. \k 36, figured 

 vol. 3, pi. 60, f. 2), B. laciniata Bii>i\ (vol. 2, p. 37), QtylocheiUu linen- 

 latus Goulu"(vo1. 2, p. 3*7), 8. longicauda Q. et G (vol. 2. p, 37, figured 

 vol. :\. ])1. 60, f. 3), 8. quercmus Otavtv (vol. 2, i>. 37), ieJAfci pfcS Rwlfl 

 (vol. 2, p. 35, figured vol. 3, pi. 59, f. 7), A. vin-ujeru q.. A. oifrina ELura 

 A. rufa Q., A. .striata Q., A. imdata Rang (vol. 2. |». 35). 



