1894. PROCEEDINGS OF THE NATIONAL MUSEUM. 145 



MARGARITrPHORA FIMBRIATA, D u n k e r. 



Valves only. 



Pichiliuque Bay; Station 2828, 10 fathoms, off Lower California; 

 Albatross. 



PERNA JANUS. Carpenter. 



Several examples. 



La Paz, both Fisher and Forrer (No. 73560, U. S. N. M.). 



I have three well-marked specimens before me, which agree with 

 Dr. Carpenter's description in the Mazatlan catalogne, pp. 151,152. 

 The description says: "The sculpture of the valves, of which the under 

 is smooth, the upper ornamented with fine, radiating stria?, etc.;" two of 

 the specimens, however, show the radiating strije on both valves. Car- 

 penter gives the measurement of his "the largest, long, (the diagonal 

 of the lozenge) 1.12; hit. 0.68, etc." inch. 



My largest example (Fisher's) measured in the same way, gives the 

 following: Length, 2.25; breadth, 1.20 inch. 



PERNA JANUS, C a r p e n t er ; variety. 



Two examples. La Paz (No. 73561, U. S. N. M.), Forrer. 



This is an interesting intermediate form, which unites in the individ- 

 ual before me the characters of Dr. Carpenter's Janus and Orbiguy's 

 Chemnitzianum. The greater portion of the exterior, exhibits the 

 coarse, laminated growth of the latter generally exhibited in the species, 

 and is posteriorly produced and elongated as is common in said form. 

 The later growth, however, shows on the edge of the posterior side 

 near the dorsal line, as well as on the anterior side, towards and extend- 

 ing to the ventral margia, the radiating striie, which Carpenter refers 

 to as a characteristic of P. Janus. The specimen is foot or hatchet- 

 shaped, and measures 1.12 inches in length, 1.61 inches in breadth. 



PERNA CHEMNITZIANA, Orb i guy. 



Several specimens. 



Pichiliuque Bay (one good example); Station 2828, off" Lower Califor- 

 nia, in 10 fathoms (No. 102098, U. S. N. M.); Albatross. 



Family M y T i l i d ^. 



MYTILUS MULTIFORMIS, Carpenter. 



Several suecimens. Tres Marias (No. 41623, U. S. N. M.). 



SEPTIFER CUMINGIANUS, Dnnker. 



Station 2827, 10 fathoms shelly bottom off' Lower California, Alba- 

 Proc. N. M. 94 10 



