Ill* 



'All our knowledge of the animals being in the papers of Clark and 

 Stimpson, it is not thought necessary to repeat their tan ments, 

 All the measurements are in decimals of an inch. 



Family CECID.E, Gray. 



Testa nucleosa spiralis, postea tubularit, reoularis, haud affiaa • 



apertura orbicular!. 

 Operculum corneutn, multispirale i maraine haud fimbriate. 

 TurritellieUs, pars, Forbes, Stiinps., Woodw. 

 Fermetidce, pars, Clark. 



Genus Cecum, Fleming. 



Testa nucleosa planata : animal una in plana solute orbiculari 

 crescens : testa animali crescente iterant iterumque deeoUata, 

 septo regulari, varie const ructo, pari ma decoUatam t 'ewe nte ,• 

 superficie seu annulata, seu lirata, sen Levi ; apertura pterum- 

 que primum constricta, postea expanaa. 



Operculum concavum seu subplanatuni ; sutura seephts Hnea ele- 

 vat a instruct a, inter dum Icevi. 



Syn. Ceecalium, Macgil. — Brochus+Cornuoides, Brown. — Odon- 

 Una, Zborz. — Odontidium, Phil. — Ccecum, Forbes & Hani. — DetUa- 

 Uopsis, Clark, MS. — ? Cornicu/ina, Miinst.* — Dentalium, Orthocera 

 seu Creseis, pars, auct. 



The distinguishing characters of the restricted genus are (1) the 

 frequently decollated, orbicular growth, the nuclear whirls being in 

 tin- same plane as the adult; and (2) the concave or flattened oper- 

 culum. 



Sect. A. Elephantt mm . 



Cceca insigniora ; t. tereti, elongata, regulari ; ttdulta litis lon- 

 gitudinaliter sculpta ,• apertura parum declwi. 



The shells in this group are like a minute DentaUum elephantsmum, 

 and are distinguished by their (comparatively) large sise, tapering 



form, and longitudinal sculpture. They are for the most part rare 



1. Cecum subspirale, Cpr. 



C. {Elephantulum) t. maxime eloni/ala, I, ,itis.s,,ne augeute, tetUtia- 

 sime lirata, litis paralltl'ts ; juxta aprrt 'uram aaai'/u subtu- 



mattes septo mucronato, superficie subplanato, mucrone tate~ 



rali, dextrorsum sito, parvo ; apic- rotutldai alt ■ 



* The Cornicnlina Ekrenbergi* of Monster, ' Beitrage tm Geognoak nod Pe- 

 tr.ta. t-n-kunde des SudoStUchen Tirol*,' 1841, pp. 118, 119. pi. 1 -' I 

 is described and figured as a chambered Cephalopod, the alpha 

 at the narrow end being also described and figured ni tin It i< 



Groin the Middle Tertiariea of Castelurquato (Parma), and onl] hah a line In 

 Ingth; ami is (opposed by Mr. Woodward, Man. MoiL i an taper- 



observed Ccecum 



