118 TIIK NAUTILUS. 



anterior with apex pointed, posterior quite sliort ; ligament and 

 resiliiiin rather short and slight. 



Long. 4.2, alt. 3.(j, diam. 3 mm. (lOO : 80 : 71). 



Long. 3.3, alt. 2 (j, diam. '2.3 mm. (lOU : 79 : 70). 



Hal).: British Columbia, a])pareiilly widely distributed and 

 coninioii, and rather varial)le with respect to size and shape (no 

 doul)t, also in Washington, etc.). Vicinity of Esqnimalt, collected 

 by Mr. Taylor over twenty years ago, sent by Justice F. II. Latch- 

 ford, No. G3G2 cotypes with the lot in Mr. Latchlord's collection, 

 and lo's sim|)ly marked " B. C." at least some oi' them from that 

 vicinity, are in various collections ; Chilliwack Creek and Lake, 

 B. C, collected by a member of the Canada Geol. Surv. staff, sent 

 by Mr. Whiteaves ; a marsh, Duncans, B. C, received from Mr. A. 

 W. Hanham. The first specimens were received in 189a, and the 

 species has been regarded as distinct ever since. 



P. farcdtum, n. sp. — Mussel oblique, medium inflated, superior 

 margin little curved, posterior and inferior forming one continuous 

 curve to the rounded-angular anterior end, or the poslcjrior margin 

 slightly subtruncate ; supero-anterior slope at an angle with the 

 upper margin, well marked, straight or little curved, at an angle of 

 alt. 4.j° to the longitudinal axis ; beaks slightly behind the middle, 

 rather large, rounded or slightly flattened on top ; scutum and 

 scutellum slightly marked, small ; surface polished, with slight^ 

 shallow stria); color pluml)eous around the beaks, straw along the 

 margins, the two shades not sharply defined, shell subtranslucent in 

 the |)lumbeous area, rather opa(]ue in the light zones; hinge mod- 

 erately strong, right cardinal tooth curved with the posterior part 

 bifid, the outer, or posterior, shank s<'parated by a groove even 

 aliove, straight or curved with the convexity below, left anterior 

 short with apex rounded, posterior oblique, slightly curved, the space 

 between them wide posteriorly ; outer lamitue of the right valve 

 small ; ligament and re.>ilium short, moderately strong. 



J>ong. 4, alt. 3.G, diam. 2.3 mm. (I HO : 90 : .57). 

 Hab.: Green Lake, Seattle, Washington, collected by Mr. P. B. 

 Randolph, with P. ithilioeiise Roper and others; types ace. No. 3896 

 b, pait, of the Carnegie Museum, Pittsburgh. Probably none of the 

 specimens are full-grown. The mussel resembles some fnrms of P. 

 varlahile Pme., but is more oblique, the color is different, and the 

 cardinal teeth are maikedly different ; named from the strongly bifid* 

 or bifurcate, v\"\\i cardinal. 



