PIIYLOGENY OF FUSUS AND ITS AIJJF.S. 73 



calatcd spirals appear carl}-, possibly in the second whorl. The lines 

 of growth produce strong cancellations. On the last whorls the ribs 

 have disappeared, and the spirals have become compound from re- 

 peated intercalation. The lines of growth crossing these produce a 

 lattice type of cancellation. 



Locality: U. S. Fish Com. Sta. 2676, 407 fathoms on fine sand off 

 Cape Fear N. C. 45.8° F. temperature. 2 spec. (Xat. Mus. 87487). 



Habitat: Guadaloupe, W. I. (Crosse). 



FUSUS HALISTREPTUS Dall. 



1889. Fusus lialistrcptiis Dall, Blake Moll., vol. 2, p. 168, pi. 35, fi{?. 7. 



This species was well described by Dall. The early whorls have a 

 distinct bicarinate aspect from the strengthening of the spiral below 

 the central one. Intercalation begins in the earliest whorls preserved 

 in the specimen. In the later whorls the shoulder becomes flattened 

 and the ribs become subdued, being far apart and narrow. In the 

 early ephebic whorls the flattening of the shoulder is arrested, but the 

 central spiral continues as a keel which is sharply noduled by the faint 

 ribs which persist throughout. The primary spiral next below the 

 central one repeats the characters of the latter in a milder manner. In 

 the final whorls the shoulder becomes relatively more convex, and the 

 intercalations triplicate. 



Locality and Habitat: U. S. Fish Com. Sta. 2655, living in 338 



fathoms, Little Bahama Bank, bottom sandy. Temp. 47.5° F. (Dall) 



(Nat. i\Ius. 93333). 



FUSUS COUEI Petit. 



1853. Fusus couei Petit, Journ. de Conch., T. 4, p. 249, pi. 8, fig. i. 

 1889. Fusus couei Dall, Blake MoU., vol. 2, p. 167. 



The specimens seen of this shell are smaller than Petit's specimen. 

 The shoulder slopes more upward, the suture is less impressed and the 

 spirals are less strong. 



The protoconch is somewhat depressed and not so typically Fusoid 

 as in the species of Fiisits generally. There are two whorls, the sec- 

 ond with fine narrow riblets which pass downward about a third the 

 width of the whorl, then forward, forming at first a concavity -and then 

 becoming gently convex, thus describing an outline like a reversed 

 letter S. The riblets become more closely crowded and broader toward 

 the end of the protoconch and no strong varix appears. The proto- 

 conch thus appears to merge into the conch. The ribs of the early 

 conch are broad, low and rounded, with a mere linear depression 

 between them. They extend straight from suture to suture, and 

 are very regular. They are crossed by narrow elevated spirals, which 

 are increased by the intercalation of secondary ones in the last portion 

 of the ribbed spire. The ribs disappear at the beginning of the fifth 



