1897.] NEW YORK ACADEMY OF SCIENCES. 157 



mensal Lepidometria. Specimens of Nephthys, Oniiphis, Mal- 

 clane and Clymenella were also taken, while here and elsewhere 

 a Serpula whitens the surfaces of the rocks with its calcareous 

 tubes. The lamellibranchs are abundantly represented by both 

 varieties (i. e., var. petitii, and vSiV.ruderata) of the common clam 

 of the Oregon markets, Tapes ataminea, as well as Saxidomus 

 squalidusf obtained near high water-mark, and Mija arenaria is 

 not uncommon. Nearer low water-line, " the Great Washington 

 clam," Schizolhserus nuttalli,^ makes its home in the sand often 

 burrowing to a depth of nearly two feet. When pursued it is 

 said to rapidly burrow to greater depths and thereby often 

 effect its escape, but this we iiave not directly verified. When 

 reached, it was often found with its foot extended as though in 

 the act of burrowing. Considering the enormous size of tlie form 

 (fulh' IT. 5 cm. by 13.5 cm.) the shell is relatively quite smooth 

 and fragile like most deep burrowers, and is easily broken by the 

 spade or even the fingers. The large cockle, Cardium corbis, a 

 smaller brightl}' colored Cardium, and several Tellinids (Psam- 

 mobia, Macoma, etc.) are also to be met with. In recalling the 

 thin, fragile and often gaping shells generally possessed by long 

 siphoned and deep-burrowing clams (Mya, Tellinidas, Hchizo- 

 thserus, etc.) as contrasted with the firm, ribbed and tightly clos- 

 ing valves so often possessed by the shorter siphoned and more 

 surface living forms (Veneridse, Cardiidse, etc.), it seems not 

 improbable that these respective characters may have been de- 

 veloped in adaptation to habits. A form by burrowing deeph' 

 might obtain thereby greater security and require a less power- 

 ful valvular protection, while an exposed surface living species 

 might be benefited by developing a firm and compact shell.f 

 The smootb, narrow and elongate character of so many burrow- 

 ing clams (Solen, 31ya, the Tellinidoe) is, as is well known, to be 

 conceived as adaptations to the burrowing habit, better enabling 

 them to cleave the sand. 



A small white crab (Pinnolhei'es) occurs very frequently in 

 the branchial chamber of both Schizothcerus nuttalli, and Cardium 

 corbis. A small yellowish green Dendrocoel Turbellarian was 

 obtained from under the rock near high water-mark towards the 

 western end of the sand flats. It was observed depositing eggs 

 during the month of July. The Ecliinoderm fauna is mainly 

 represented here by Dendraster excentricus. In some localities, 

 broad areas fully an acre in extent were so thickly packed with 

 them that at least half a dozen were crushed at every footstep. 



*Evidently Lutraria maxima of William Cooper. Nat. His. Wash. Terr., isr)<). 



t Pecten, it is true, is exposed aud yet has a shell remarkable for its thinness, but 

 this is obviously an adaptation to its active habits which doubtless proves of compen- 

 sating advantage. 



