MONOCEROS. 



Plate I. 



Geuus MoNOCEROS, Lamarck. 



Teda ovata, spird nunc elatd, nunc sabdcpressd, mifractu 

 uUimo iiiflato, basi emarginato ; columelld ampld, de- 

 premitsculd, interdum subludktmcie plicatd ; Inbro 

 processu deutiformi, aeid'tMimo, elomjato, prope basin 

 ormato. Operculum, comeum. 



Shell ovate, spire sometimes elevated, sometimes a little 

 depressed, last wliorl inflated, emai-ginated at the 

 base; columella large, rather depressed, sometimes 

 indistinctly plaited, lip armed near the base mth a 

 very sharp elongated dentil'orra process or tooth. 



The genus Monoceros of Lamarck, introduceil almost 

 simultaneously by De Moutford under the title of Uiii- 

 wrnus, is characterized solely by the conspicuous tooth 

 which becomes developed tovrards the base of the lip ; the 

 genus is not, however universally admitted, the animals 

 of Monoceros and Purpura are the same, and there are 

 many of the Purpur/t which exhibit indications of a tooth. 



The species are very limited in number, and no additions 

 have been made to the catalogue during the last few years. 



Species 1. (Mus. Cuming.) 



MoNOCEKOS uxicARiNATUM. Mon. tcstd ovato-oUoiujd, 

 subfusiformi, anfractibus superni anyuhdk, adangidum 

 subobsolete carinatis, transversim impresso-striatis, aper- 

 tura faiwe denticulatd ; cinereo-albicante, areis inter 

 strias fusco-nigricante articidatis, aperiiird albicante, 

 rufo interdum exiliter tinctd. 



The one-keeled Monocekos. Shell ovately oblong, 

 somewhat fusiform, whorls angulated roimd the upper 

 part, rather obsoletely keeled at the angle, trans- 

 versely impressly striated, interior of the aperture 

 denticidated ; ashy white, spaces between the striae 

 articidated with brownish black, aperture whitish, 

 sometimes faintly tinged with red. 



Soweeby, Conch. lUus. Monoceros, tig. 5. 

 Purpura spicata, De Blainville. 

 Purpura engonata, Conrad. 



Hob. Santa Barbara, California (under stones at low water) ; 

 NuttaU. 



This is unquestionably a true Monoceros; M. Kiener, 

 who includes the species among his ' Pourpres buccinoides,' 

 under De BlainviUe's name of P. spirata, has represented 

 a specimen in an early stage of gi'owth before the tooth is 

 developed. 



September, 1846. 



Species 2. (Mus. Cuming.) 



MoNOCEEOS PUNCTATUM. MoH. testd aubglobosd, crassd, 

 Irevigatd, labro intus denticulate, lutescente-albd, fasciis 

 tribus nigripunctatis cinctd, aperturd rufo pallida 

 tinctd. 



The dotted Monoceros. Shell somewhat globose, 

 thick, smooth, bp denticulated within ; yeUowish- 

 white, encii-cled with thi-ee black-dotted bands, aper- 

 ture faintly stained with red. 



Gray, Zoology of Beechey's Voj'age, p. 124. 

 Purpura lapilloides, Conrad. 



Mab. Isle of Cocos, north-west coast of Mexico (on the 

 rocks) ; Capt. CoLnett. Santa Barbara ; NuttaU. 



This species, although found in the same locality with the 

 preceding, is perfectly distinct, and may be recognized by 

 its more solid globose structure and dotted bands. 



Species 3. (Mus. Cuming.) 



Monoceros giganteusi. Mon. testd oblongo-fusiformi, 

 medio ventricosd, basi attenuatd, lavigatd, transversim 

 obsolete costatd, columelld in/erne subplanulatd, labro 

 simpUci, irdegro, apei-turd ampld ; palUde luteo-fusces- 

 cente, costis saturatioribus, apertura fauce croced. 



The gigantic Monoceeos. Shell oblong fusiform, ven- 

 tricose in the middle, attenuated at the base, smooth, 

 transversely obsoletely ribbed, columella a little flat- 

 tened towai-ds the lower part. Up simple, entire; 

 aperture large; pale yeUowish brown, ribs darker, 

 interior of the aperture yeUow. 



Lesson, Voy. de la CoquUle, (1826), MoU. p. 405. p. 11. 

 f.4. 

 Monoceros Tusoides, King, Zool. Joiu-n. (1830). 



Hoi. Conception, ChiU (m rocky places at a depth of from 

 thi-ee to five fathoms) ; King. 



Very few examples of this fine species have yet been 

 found m good condition ; M. Lesson appears to have pre- 

 ceded Capt. King in the discovery of it by three or four 

 years. 



Species 4. (Mus. Cuming.) 

 Monoceros brevidentatum. Mon. testd ovatd, crassd, 

 spird brevi, snbacuminatd, transversim impresso-striatd, 

 obsolete triseriatim nodoso-costatd ; cinereo-nigricante, 

 macidis albis cinctd, aperturd albd. 



