NO. nil. PROCEEDINGS OF THE NATIONAL MUSEUM. 363 



The jaw, on the whole, resembles that of Thy.sanophora, as figured 

 by Pilsbry. The teeth of the radula are also of the normal bulimuloid 

 type with about o-") laterals on each side of the rhachidian tooth. The 

 latter is symmetrical and has the lateral cusps practically absent, 

 though there is a shoulder on the side of the median cusp where the 

 lateral casps are usually situated. The lateral teeth are very similar; 

 the outermost are shorter and wider and have the inner and outer 

 cusp more separated or less fully developed, but otherwise, as in 

 B. alternatus, resemble the inner laterals. The radula as a whole 

 differs chiefly from that of B. alternatus m having the individual teeth 

 a little wider m proportion to their height. 



BULIMULUS (ORTHOTOMIUM) RAMENTOSUS, Cooper. 



(Plate XXXI, fig. 8.) 



Ehodea caUfornica var. rcuueniosa, Cooper, Proc. Cal. Acad. Sci., 2 ser.. Ill, p. 



102, 1891. 

 Columna ramentosa, Cooper, loc. cit., p. 215, 1892; p. 338, 1893. 

 Plicolumna ramentosa, Cooper, Ioc. cit., Y, p. 104, June, 1895. 



Kear the edge of lagoons near San Jose del Cabo, Lower California, 

 Bryant and Eisen ; also in the mountains by Eisen, Vaslit, etc., but the 

 altitude is not stated. (Cooper.) 



This species has precisely the nucleus of B. artemesia and the exter- 

 nal appearance of the animals as far as could be determined in the 

 very contracted specimens does not differ. The jaw is almost exactly 

 the same size as that of B. artemesia, and agrees in every particular 

 in the mode of its construction. If a number of jaws of the two spe- 

 cies were mixed no one could determine to which species any partic- 

 ular jaw properly belonged. The teeth and radula agree with equal 

 closeness except that it is somewhat narrower, the formula being 

 28: 1: 28 in the specimen examined, and the outermost laterals were 

 proportionately a little wider than in B. artemesia. 



The distinctions between this form and Rhodea have been pointed out 

 in the sectional diagnosis, but it may be as well to call attention to 

 some minor details. The base of the last whorl in B. ramentosus is 

 rounded and the constriction of the peripheral part of the whorl is 

 variable in different specimens. It would alaiost seem as if the con- 

 striction and the gyration of the pillar were in some way correlated, as 

 the pillar above the last 2 whorls is not gyrate, though somewhat tor- 

 tuous, and consequently the perviousness of the axis does not extend, 

 as supposed by Cooper, to the entire axis, but only to that part of it 

 included in the last whorl and a half or two whorls. The columellar 

 muscle is exceptionally long, and attached for several whorls, so that 

 it is very difficult to withdraw the animal from its shell, even after it 

 has been long in alcohol. The axis appears to be destitute of any 

 lamelhe, plications, or projections o f any kind. In fact, the creature, so 

 far as its shell is concerned, is a very attenuated Lepfohyrsm with its 

 gyrate axis continued into the adult state, whereas in the ordinary 



