270 bulletin: museum of comparative zoology. 



39. Serpula nannoides, sp. nov. 



Plate 2, fig. 8. 



The present form, as represented by the several type-specimens, is greatly 

 exceeded in size by 5. vermicularis and S. splendens. From both these species 

 readily distinguishable in having the collar-fascia relatively much longer and 

 more prominent, greatly exceeding the following fasciae instead of being 

 smaller than them. Collar-setae stouter and darker than the others and 

 differing in structure as usual; bayonet forms with spurs stouter than in 

 vermiadaris, rounded. Thoracic membrane at lower end below on each side 

 with two caudally directed, triangular lobes or flaps of which the lower is 

 usually much larger, the upper one sometimes scarcely obvious; on ventral 

 side the collar-membrane protrudes forward at middle where it is simply 

 rounded, not at all incised. Operculum funnel-shaped, thin and less rigid 

 than in vermicularis, more or less readily collapsible. Number of crenations 

 along edge of operculum about ninety. Secondary operculum not observed 

 in the types. 



Greatest width, near 2.5 mm. 



Locality. — Calif.: Crescent City (A. Agassiz). 



Type — M. C. Z. 511. Paratypes.— M. C. Z. 2,131. 



40. Crucigera hespera, sp. nov. 



Plate 2, fig. 9. 



The type of this species is notably smaller than that of C. zygophera (John- 

 son) with which it has been compared. It is obviously different in the form 

 of the operculum. The operculum proper is similarly regular but is decidedly 

 narrower, not truly campanulate, the radii not flaring out distally but with 

 their acute apices in a distal median position on each. Radii twenty-five in 

 number. As in zygophera there is on one side but a single rounded, ectally 

 flattened or concavely depressed lobe beneath which the distally abruptly 

 constricted stalk is attached. On the other side are two more prominent 

 lobes; these are more widely divergent than in zygophera and instead of being 

 straight are distally geniculate, the short apex extending up at right angles 

 to the axis of the basal part and well rounded. Secondary operculum more 

 slender, distally less bluntly rounded than in zygophera. 



Width across thorax, 2.5 mm. Width across operculum, 1.8 mm. 

 Locality. — Calif.: Mendocino (A. Agassiz). 

 Type.— M. C. Z. 164. 



