CEPHALOPODA. 49 



Aturia {Nautilus) zic-zac, but it is narrower towards the margin, which circumstance 

 gives a triangular form to the aperture. The septa (Tab. VIII, fig. 3) are very concave, 

 and present on each side a broad undulation, with a deep sinus-like depression 

 caused by a lateral lobe, more developed in this species than in N. urbanus, although 

 not attaining the size and importance of that which distinguishes N. Parkinsoni. 



The dorsal lobes arc much recurved and obliquely truncated ; the siphunclc is 

 moderately large, placed very near to the dorsal margin, and continuous. The striee 

 of growth towards the middle are suddenly bent backwards in deep undulations. 



This species, which attained a size of 10 inches in diameter by 4'2 in. across, was 

 first obtained by Mr. Wetherell from the tunnel made at Chalk Farm for the Birmingham 

 Railroad. It has also been found in the cuttings now in progress between Whetstone 

 and Barnet for the Direct Northern Railroad, and it occurs at Sheppy and at Bognor, 

 where it is very common. 



No. 12. Nautilus Parkinsoni. F. E. Edwards. Tab. VII. 



Nautilite. Parkinson. 1811. Organic Remains, p. 105, pi. 7, fig. 15. 



N. testa discoided, aperturd elongato-ellipticd, parietibus convexis ; umbilicis (?) ; septis 

 extus concavis, in utroque latere angulariter lobatis, siphone, prope margines dorsales posito 

 perf oralis ; lobis lateralibus brevibus, subtriangularibus, mucronatis ; lobis dorsalibus talis, 

 perparum concavis, ad extremitates attenuates, re/lexis. 



Parkinson, in his work above cited, described the remains of a Nautilus, purchased 

 by him at the sale of Dr. Menish's collection. These remains, which consist of the 

 casts of three chambers, afterwards came into the possession of Mr. Sowerby, who 

 has placed them at my service. Parkinson was ignorant of the locality whence 

 they came ; but from their mineralogical character, the matrix being, in fact, the 

 substance known as cement-stone, it was supposed that they were found at Harwich. 

 Lately the Rev. Thomas Image, of Whipstead, near Bury St. Edmunds, has 

 forwarded to me for examination similar remains, unquestionably obtained at 

 Harwich, and consisting of the casts of two chambers, rather smaller than those 

 in Parkinson's specimen, and in a matrix precisely similar. The question, therefore, 

 as to the locality of Parkinson's specimen is set at rest. 



These remains are particularly interesting, from the circumstance that in them the 

 angularly-lobed septum which characterises Aturia (Nautilus) zic-xac, and in that shell is 

 accompanied by a strictly dorsal siphuncle, is associated with one which, although very 

 excentric, is still so truly discal, as to prevent the shell being removed from the present 

 genus. The form of the septum is a good specific character, but it cannot be relied 

 upon as a generic distinction. The Nautilus Parkinso?ii, therefore, although in general 

 appearance it closely resembles Aturia, must, in fact, from the position of the siphuncle 



'7 



