Part II - State of New Jersey

1-10 CRETACEOUS FOSSlLSproduced on pl. 1, fig. 2 is drawn only in its outline and so is unsuitableas the type specimen. Furthermore, this specimen could not be positivelyidentified by the writer in the type-lot of Morton. This leaves thelarge specimen reproduced on pl. 1, figs. 1, 3 .as the only possible choiceand this specimen is herewith salectccl as the leetot,ype of Belemnitel/aan~ericana (Morton). This very large guard, ~hich is actually the largestrepresentative of Belc?~tn,itellamericana (Morton) s. lato' seen bythe writer, is reproduced on pl. 76, figs. la-le, as the original figures and.~lescription of Morton (1630a-e; 1834) arc somewhat imsatisfnctory.The original figure of RIorton (1830b, pl. 1, fig. I), however imperfect,shows clearly the asymmetry of the apical quarter of the guard and ofits mucro in the ventral aspect. This asymmetry is actually present ont,he original specimen and is clearly ~isible on pl. 76, figs. la, le. Thisputs the identification of the leetotype of R. an~nricana (Morton) heyondany donbt in the opinion of the writer. It is fclt, however, thatthis asylnmetry is pat,hologic;~l in its nature, as its appearance and ashort and deep longitudinal groore associated with it are too irregularin their outline to be esplaincd in any other may. Besides, similar featuresonly occur in the pathological (crippled) specimens in any hithertodescribed represontatires of the family Belemnitellidae Pavlom. Thesectioning of other specimens of Relei~lnitella aincricasa s. 1. and alliedXorth i\merican forms has sho~nthat similar malformations are duet,o the juvenile guard having been broken and regenerated with subsequentloss of symmetry and normal proportions of the grown-up specimen.Even similar apical grooves hare becn observed sometimes. Thercfore,in spite of the fact that the guard has not been split, it seems safeto assuu~c that also the lcctotype of Belen~?~itclla at~lcrieana s. 1. hassulkred an injury of its juvenile g~~arcl (probably was broken) hutsurvivcd it and managed to hcal the fracture and to reach a very large(one could say gigantic as Belamnitella go) size.It is rather nnfortunate to have R pathological specimen for thelcctotype of Belo~l?litellantericonn (Morton) ; yet the writer does notsee any escape route, the only figure of the ot,her specimen publishedsimultaneously mit,h it being useless and the specimen itself apparentlylost. Besides, the ahove described malformation is only a slight one anddoes not destroy or strongly distort the normal proportions of theguard or its external sculpture. Thus, it does not impair the usefulnessof the leetotype as a type specimen once it is recognized as such. Apartfrom it the specimen chosen as lectotypc is almost complete, very wellpreserved, and quite typical of Rolentnitella amoricn@a s. 1. as nnderstoodby the writer.Illorp11ology.-The description of the n~orphology of the guard ofBelemnitella americana s. I. is made rathcr difficult by the exceedinglygreat variability of almost all its morphological characters. The rangeof the variation is, in fact, so great that the writer is tempted to doubtthat all the extreme morphological Hclcmnitella-like forms studied by'This will be abbreviated as B~lemnitellr ameriesna r. I. throughout this chapter.NEW JERSEY GEOLOGICAL SURVEY