416 G. C. Crick— On Goniafitcs, Nautilus, etc. 



regarded by Hyatt x as the highest type of Nautiloidea, since with Us 

 "ventral V-shaped lobe and ventral siphon " it is "so like Gonintitcs 

 that it can be separated only by its young and the gradations of 

 forms which connect it with certain well-known Nautiloids." 



The original of Phillips' fig. 66 is simply an internal cast of four 

 loculi ; there is no trace of the test. It has the following 



dimensions : — 



mm. 



Length ... 48 



Height of whorl at anterior end ... ... 22 



Greatest thickness ,, ,, ... ... 19 



Width of periphery „ ,, ... about 12 



Height of whorl at posterior end ... 16-5 



Greatest thickness ,, ,, ... 15 



Width of periphery ,, ,, about 9 



The greatest thickness of the whorl is at about one-third of the 

 height of the whoid from its inner edge. The periphery is flattened, 

 and has no central channel such as Phillips represents in fig. 67 ; 

 the siphuncle is well below the surface, its centre at the anterior 

 end of the specimen being 2-75 mm. from the periphery. The 

 peripheral (or external) saddle of the suture-line is depicted 

 (fig. 68) much. too acute ; the anterior part of the specimen is here 

 broken a little, causing this saddle to appear more acute than it 

 really was. 



A careful comparison with the type has enabled the writer to 

 identify with this species a small but exceedingly well-preserved 

 specimen (see accompanying figures), now in the Gilbertson collec- 

 tion in the British Museum (No. C. 5336), and to characterize 

 Phillips' species more fully than has hitherto been done. It has 

 the following measurements : — 



mm. 

 Diameter ... ... ... ... ... 43 



Height of outer whorl ... ... ... 17 



Width of umbilicus (suture to suture) ... 15 - 5 

 Greatest thickness... ... ... ... 16 



Width of periphery ... ... ... 11 



The specimen, which is probably not quite complete, consists of 

 nearly two whorls. There is a large central vacuity. The first third 

 of the first whorl is free. The apex has unfortunately been very 

 slightly chipped in clearing the specimen from the matrix. The first 

 chamber is conical, a little more than 1 mm. deep, and with a ventro- 

 dorsal diameter of 1-5 mm. at its anterior end. The free portion is 

 sub-circular in section, but at the completion of the first half whorl 

 the periphery is distinctly flattened and 3 - o mm. wide, the height or 

 ventro-dorsal diameter of the whorl here being 4-5 mm., the greatest 

 thickness being at a short distance from the inner edge. The 

 shell increases rather rapidly, but maintains about the same form of 

 transverse section. 



Unfortunately the free portion of the fossil bears only fragments 

 of the test. Near the apex the whorl is crossed by transverse lines 



1 A. Hyatt, "Fossil Cephalopoda in the Museum of Comparative Zoology": 

 Proc. Anier. Assoc, for the advancement of Science, vol. xxxii, 1SS3, p. '3'6o. 



