OF CONCHOLOGT. 169 



Next in order, and to the south, comes the species described 

 by me in this paper, which, as suggested, connects the northern 

 with the semitropical forms. 



Tiie form to which I have given the name of pauc'diratum 

 seems to have escaped the keen search of many experienced col- 

 lectors, as not a single specimen of it was detected by either of 

 the gentlemen above named, and it was not discovered until Mr. 

 Hemphill visited the small islands off San Diego, known as the 

 *' Coronados." As the mainland has been pretty well examined 

 along here, it is probably an insular species, and a thorough 

 investigation of the islands may prove it to be quite common. 

 Its distribution may be somewhat eccentric, like that of the fine 

 Purpura planospira. Lam., which is seldom found upon the main- 

 land, and confines itself, with aristocratic exclusiveness, to So- 

 corro Island, one of the islands off the west coast of Mexico, 

 known as the Revillagigedos. 



In the third edition of Dr. Jay's catalogue (1839) a species of 

 Monoceros, 31. phiinheiim, Kiener. is credited to Upper Califor- 

 nia ; to what shell this refers I am not aware. [PseudoUva 

 [Bucciniim~\ plumhea, Desh. W. H. Dall). Kiener's species 

 does not appear in the fourth edition of said work, but " M. pluin- 

 heurn, Chemn.," the habitat of which is given as " Africa Merid." 



Inhabiting a lono; reach of coast, extendinoj the entire length 

 upon the ocean side of the peninsula of Lower California, a dis- 

 tance of nearly eight hundred miles, as well as at Cedros and 

 other islands we find the next species in order, Monnceros lugu- 

 hre of Sowerby ; it is also found up the Gulf of California, and 

 is repoi'ted from Guaymas on the eastern shore. In many places 

 it is exceedingly numerous, and is perhnps the commonest species 

 in collections ; specimens from different points vary considera- 

 bly, the outer coast or oCean side shells being the most robust, 

 and the Gulf specimens more elongated. I did not obtain a 

 specimen at Acapulco nor hear of its being found so far to the 

 south. 



It is not reported in the Mazatlan catalogue of Reigen's col- 

 lection ; in Kiener it is credited to "Peru and Californin," but 

 as Kiener, Reeve, Sowerby and many others of the European 

 authors seem, to use a California phrase, to have " gone it blind" 

 on habitat, in questions of geogr;iphical distribution, their state- 

 ments of localities must be taken with great caution. In the 

 Tankerville catalogue it is referred to as M. c^/matum, Sby., in 

 H. and A. Ad. Genera, as 31. cymatium, Soland., and neither 

 of Conrad's names are given for the California species by the 

 last named authors. M. engonatum, Conr., is enumerated in 

 the list under Blainville's name ^^spirata" and 31. lapilloides, 



