The Invertebrate Fauna of the Uitenhage Series. 183 



Bochianites as a separate genus or as a sub-genus of Baculites might, 

 perhaps, be considered doubtful, and on this point G. Boehm, who 

 adopts the name," has refrained from expressing an opinion. Sarasin 

 and Schondelmayer ascribe a generic value to the name, and con- 

 sider that a comparison of the septal sutures indicates that 

 Bochianites and Baculites have originated separately ; f the dif- 

 ferences revealed by such a comparison are, in fact, so striking and 

 so constant that with present knowledge it appears to be a reasonable 

 and expedient course to regard these forms as generically distinct. 

 In Bochianites there is a siphonal lobe, an anti-siphonal lobe, and 

 on either side one main lateral lobe. These are relatively narrow 

 and of almost equal depth. An important distinctive feature is the 

 trifid termination of the lateral lobe. On either side there are two 

 relatively broad saddles, each divided fairly symmetrically by a 

 narrow subsidiary lobe. There are thus typically only four main 

 lobes and four saddles, though in some forms (for example B. undu- 

 latus von Koenen) the lateral saddle is so deeply divided that it 

 might be almost regarded as forming two saddles separated by a 

 lobe less deep than the lateral lobe. To obtain the septal suture 

 of Baculites, we must imagine the subsidiary lobe of the lateral 

 saddle to be so deepened as to constitute an additional lateral lobe ; 

 at the same time the anti-siphonal lobe becomes very much less 

 deepened, while the first lateral lobe should have a paired instead 

 of a trifid termination. These relations are very well revealed by 

 a comparison of the suture-line in Bochianites neocomiensis J and 

 Bochianites ivateringi with that in Baculites baculoides \\ and 

 Baculites bohemicus.^ 



There can be no doubt that the Uitenhage specimens must be 

 referred to Bochianites, as clearly indicated by the course of the 

 lobe-line. One of the chief distinctive characters of the form here 

 dealt with appears to be the absence of surface ornaments, and even 

 allowing for imperfect preservation, it may be regarded as certain 

 that the available material would have shown definite traces of 

 ribbing if such had existed. Specimens from the clay-pit near 

 Eawson Bridge, which I think may represent the same species, are 

 much crushed, but the shell-substance is in great part preserved and 

 retains its nacreous lustre. In these there is no trace of ribbing, 

 and the shell appears to have been a smooth one. 



* G. Boehm (3), p. 26. t Sarasin and Schondelmayer (1), p. 177. 



{ d'Orbigny (1), p. 560, pi. 138, fig. 4 (1842). 



G. Boehm (3), p. 26, fig. 3. || d'Orbigny (1), p. 562, pi. 138, fig. 11 (1842). 



H Jahn (1), pi. viii., fig. 7 ; Woods (1), p. 76, pi. ii., fig. 10. 



