MOLLUSCA. 791 
Sp. Patella vulgata L., Buatnv. Malacol. Pl. 48, fig. 1, Pl. 49, fig. 1; Patella 
granaina L., Lister Conchyl. Tab. 534, fig. 13 ;—Patella compressa L., 
Listrr, Tab. 541, fig. 25, Buarnv. Pl. 49, fig. 2, &c. 
Appendix to the Cyclobranchiata. 
Nematobranchia Munxe (Cirrobranchiata BLAINy.). (An ab- 
normal, aberrant, family.) 
Dentalium L. Shell tubular, elongato-conical, subarcuate, per- 
vious at both extremities, with posterior aperture narrow, a fissure 
often extending upon the shell. Animal conical, eyes none, bran- 
chize composed of many cirri arranged in two fasciculi. 
The genus Dentalium, placed by Linnaus with Patella, and referred by 
later writers to the ringed worms, belongs in reality, according to the 
investigations of Saviany and DEsHayrss, to the Mollusca, although it is 
difficult to unite that genus with any of the other families. It forms a 
small group between the Heteropoda and Aspidobranchiata (Emarginula). 
The species are numerous; many are extinct, and occur in various tertiary 
and secondary formations. 
Sp. Dentalium elephantinwm L., Martrnt Conchyl. Tab. 1. fig. 4.4, Dusu. 
(see below) Pl. xvi. fig. 7;—Dent. Entalis L., Desu. Pl. xv. fig. 7, XVI. 
fig. 2, GUERIN Iconogr., Annel. Pl. 3, fig. 1, Cuv. R. Ani., éd. ill., Annel. 
Pl. 7, &e. 
Comp. on this genus DresHayEs Anatomie et Monographie du genre Den- 
tale, Mém. dela Soc. d’ Hist. nat. 11. Paris, 1825, pp. 321—378, Pl. rs—18. 
Family VIII. Aspidobranchiata. Shell clypeiform, in most 
not turbinate, with very large aperture, incumbent on the pectinate 
branchie. Heart with two auricles, perforated by the rectum as in 
Acephala. Organs of sex distinct, some individuals male, others 
female. : 
Lottia Gray (Patelloide Quoy and Gam.). Branchia pectinate, 
placed on the right side and forwards, often emerging beyond the 
mantle. Shell conical, often thin. 
Note.—A genus very similar to the Patella, but different in the structure 
of the branchize. Comp. Quoy et GAIMARD Voyage de l’ Astrolabe, Zoolo- 
gie, TI. 1834, pp. 349—366. Sp. Lottia testudinaria, Patella testudinaria 
L., Lam. ;—Patella virginea Muxut., Lottia pulchella Forses. Comp. 
ALDER Ann. of Nat. Hist. vit. 1841, Pp. 404—406. 
Parmophorus Lam. Shell oblong, oval, depressed, clypeiform, 
not turbinate, with margin entire, apex subincurved, not perforate. 
