APORRHAIS OCCIDENTALIS Beck 

 PI. III. Fig. 18. Length 57 mm. 



This curious shell with its long turrited spire and expanded outer 

 lip like Sirombus, combines a number of diverse characters that have 

 puzzled systematists. It has a long, cylindrical body, a prominent 

 head with long, thick muzzle, bifurcated, (Fig. 18, A) a strong, sturdy 

 foot stalk terminating in a rather short, narrow creeping disk which 

 throws itself into curious contortions. At its extreme end it supports 

 a long, narrow slightly curved operculum which overhangs both sides 

 of the foot. The creeping disk is irregular in shape, deeply wrinkled, 

 wider in front and tapering to a point behind. Near the end beneath 

 is a thick blunt process (Fig. 18 B) springing from the left side and 

 extending obliquely across the foot, an appendage, so far as I know, 

 unique in gasteropods; its function is enigmatical. The foot is pure 

 white, the rest of the body is tinged with yellow. The mantle extends 

 to the margin of the aperture. The tentacles are long and very thick 

 at the base, the eyes are prominent and supported on a thickened 

 projection at the base of the tentacles (Fig. 18, C). The tentacles 

 are brownish in color on the dorsal surface, in life they were incessantly 

 swinging aimlessly, the long proboscis is strongly bifurcated and the 

 movements which were constant were alternating. (Fig. 18, D). 

 Turritella erosa has an identical form of proboscis moving also in the 

 same alternating manner. There is a resemblance to Aporrhais pes- 

 pelicani in the lingual dentition of 7. erosa. 



The specimen studied was sent to me by Dr. Harold S. Colton 

 from the coast of Maine. Dr. Colton had had it in captivity for 

 four days. He said it had been very active in confinement, crawling 

 about the pan and up its sides and dropping off with a thud to the 

 bottom. It proved a very interesting captive. Despite its transporta- 

 tion in wet sea weed by mail for over three hundred miles it had lost 

 none of its vitality, and in its contortions the claw-shaped operculum 

 functioned evidently as an organ of locomotion, recalling the behavior 

 of Strombus to which genus Linnaeus first assigned it. 



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