192 PALEONTOLOGY OF NEW JERSEY. 



This, with tlie absence of all evidence of pallets or accessory parts, leave no 

 chance of determining to which of the subdivisions of the genus Teredo the 

 species properly belongs. 



Formation and locality. — In the Cretaceous of New Jersey, and from the 

 appearance I should suppose from the Lower Marls, but no evidence exists 

 on the labels or in Mr. Gabb's original description of any definite locality. 



GASTROCH^NIDtE. 



Genus CLAVAGELLA Lam. 

 Clavagella armata. 

 Plate XXV, Fig 24. 



Clavagella armata Mortou. Synopsis, p. 69, PI. IX, Fig. 11. Gabb, Synopsis, p. 109. 

 Meek, Check-list, p. 15. Gabb, Proc. A. N. Sci., 1861, p. 364. 



Shell small, the valves being transversely oval, moderately convex, 

 with proportionally large and tumid beaks; their disks marked, especially 

 the right valve, by strong concentric undulations. Right valve free, and 

 the left somewhat distorted in the only specimen which I have before me. 

 Tube small and compressed. 



The specimen which I have figured does not show the tubular spines 

 on the anterior margin as mentioned by Dr. Morton. But a small specimen 

 in the collection of the American Museum of Natural History, New York, 

 shows several spines, and I presume they vary considerably in this respect. 

 Dr. Morton's figure shows the existence of these spines on the cast, but the 

 form of the shell as shown there is remarkably elongated and narrowed, as 

 compared with any of those which I have observed. On that which I have 

 figured the muscular impressions are quite marked, showing the shell to 

 have been very much thickened. Judging from Dr. Morton's figure, as well 

 as from the evidence furnished by the specimen here figured, I should infer 

 that the present species would be properly classed under Stirpulina Stoliczka, 

 a subdivision of Clavai/eUa, in which the tubular spines are confined to the 

 anterior portion of valves, and not scattered along the basal margin also. 



