388 MOLLUSCA. 



nature of their hermaphroditism ; for, like the preceding ge- 

 nus, they have no copulating organ, but fecundate them- 

 selves. Their heart does not embrace the rectum, but varies 

 as to situation. But two genera of this order are known, in 

 both of which the shell never approaches in the least to the 

 turbinated form. 



Patella, Lin. 



The entire body covered with a shell, formed of a single piece, in 

 the form of a broad-based cone; a cordon of little branchial lamellae 

 under the margin of the mantle; the anus and genital orifices some- 

 what to the right and above the head, which is furn-ished with a 

 thick and short snout, and two pointed tentacula, on the external base 

 of which are the eyes; the mouth is fleshy, and containing a spiny 

 tongue, which inclines backwards, and is reflected deeply in the in- 

 terior of the body. The stomach is membranous, and the intestine 

 long, thin, and greatly flexed; the heart is forwards, above the neck, 

 and a little to the left(l). 



Some species abound on the coast of France. 



Chiton, Lin. 



A range of testaceous and symmetrical scales along the back of the 

 mantle, but not occupying its Avhole breadth; edges of the mantle 

 coriaceous, and furnished either with a naked skin or little scales, 

 which give it the appearance of shagreen, or with spines, hairs, or 

 setaceous fasciculi. Under these edges, on each side, is a range of 

 lamellar, pyramidal branchiae; and before, a membranous veil on 

 the mouth supplies the want of tentacula. The anus is under the 

 posterior extremity. The heart is situated behind, on the rectum; 

 the stomach is membranous, and the intestine very long and greatly 



(1) I separate from the Pateils!: and arrange among the TnocnoTn.n, all the 

 animals comprised in the genera, Crepidula, Navicella, Caltptii7T3a of M. do 

 Lamarck, to which I add the Capcli; and his genera Fissurella, Emarginuia, 

 and Parmophoha, or Patella ambigua, Chemn., XI, 197, 1918, I place among the 

 SciTTiBRAxcHiATA. The Umbhella, Scutus, Montf., Patella umbrella, Martini, II, 

 VI, 18, IS one of the Tectibranchiata. The Pat. anomala, Miill., belongs to the 

 Bhaciiiopoda and is my genus Orbiculus. The other species quoted by Gm. 

 remain in the genus Patella. 



