332 E. W. Berry — An American Spirulirostra. 



cuttles that habitually pass their time in deeper water, 

 or whether the shells were postmortem additions to the 

 littoral faunas in which they are found, cannot certainly 

 be determined. We can dismiss the idea advanced by 

 one writer on Spirula, that air in the shells is responsible 

 for the occurrence of that form on tropical sea beaches, 

 as rather far fetched. The common European Sepias, 

 which normally live in from 10 to 40 fathoms, come into 

 shallow water during 1 the summer to deposit their eggs, 

 but it would seem that if such a habit were invoked to 

 account for the presence of the Spirulirostra shells they 

 ought to be discovered more frequently. On the other 

 hand if chance drifted specimens from the open sea 

 account for their occurrence in the fossil record, it is 

 difficult to see why a single collection like that from 

 Tehuantepec should contain the remains of a dozen 

 individuals. 



The habits of the existing Spirula might throw some 

 light on the habits of Spirulirostra, but unfortunately 

 little is known of the former, and the number of spirulas 

 that have been taken could be enumerated on one's fingers, 

 although the shells are common enough in the warmer 

 parts of the Atlantic, Pacific and Indian oceans. The 

 single animal taken during the extended cruise of the 

 Challenger came from between 300 and 400 fathoms, but 

 appeared to have been partially digested in a fish 

 stomach, so that it sheds no light on the problem. It 

 leads, however, to the suggestion of another possible 

 means of transportation from deeper water, namely, in 

 fish stomachs. Fishes are fond t of the existing cuttles, 

 and the habit of voiding undigestible hard parts is a 

 common enough one on the part of fishes. 



Without reaching any conclusion as to the source of 

 the Spirulirostra remains in the deposits where they 

 have been found, I think the conclusion is warranted that 

 the animals were normally active pelagic types. The 

 existing Spirula is unknown in the fossil record, and its 

 openly coiled phragmocone shows no traces of having 

 ever had a guard or proostracum. Some students have 

 emphasized this point as though it were evidence of more 

 direct relationship with the original ammonite stock than 

 with the belemnoids. Such a line of reasoning, assuming 

 that Spirulirostra is related to Spirula, which seems 



