1 HOTHKIEMBUYON. 



Genus BOTHRIEMBRYON Pilsbry, 1894. 



Manual XIII, p. 1. Li par us of authors, not of Albers or Olivier. 



The shell in this group is similar to that of Bulimulus. The soft 

 anatomy is known by the work of Deshayes and Semper on B. melo, 

 and of Hedley on B. master si, tasmanicus and spencer i. 



The triangular kidney is as short as the pericardium in B. me/o. 

 The genital system in all the species examined, shows a long, slender 

 penis, corrugated inside and without papilla, tapering into an epi- 

 phallus above, which receives the vas deferens midway and the 

 retractor muscle at the apex (me/o), or has a very delicate retractor 

 attached to the membrane enveloping the vagina (spenceri), or is 

 apparently without retractor, and ends in a long, coiled flagellum 

 (tasmanicus). The oval spermatheca is upon a duct about as long 

 as the oviduct, and attached to its enveloping membrane (pi. 51, 

 h'g. 20, B. melo, after Semper). 



The jaw is thin and delicate, composed of 11 (melo), 15 (mastersi), 

 16 (spenceri), 32 (tasmanicus} plaits, which denticulate the lower or 

 both edges and converge obliquely, leaving a triangular plait in the 

 middle (pi. 60, fig. 10, B. tasmanicus, after Hedley). 



The radula has 29.10.1.10.29 teeth in B. melo, 40.5.1.5.40 in B. 

 mastersi, 32.15.1.15.32 in B, spenceri, 84.5.1.5.84 in B tasmanicus. 

 The teeth have squarish basal plates and pointed cusps of the 

 ordinary Helicid form, the centrals with the mesocone shorter than 

 or about as long as the basal plate below it, ectocones small (melo, 

 spenceri), or wanting (mastersi, tasmanicus). The lateral teeth have 

 longer mesocones and distinct ectocones. The marginals have the 

 mesocone or both mesocone and ectocone split in some species, while 

 in spenceri they remain simple, and " to the remotest marginals the 

 mesocone dominates the ectocone." 



Notwithstanding its isolation, this genus differs from South Amer- 

 ican BulimuUnse in minor characters only, so far as we now know. 

 The radula is of undifferentiated type, like that of Bulitmilus, but the 

 jaw has converging plaits as in Drym&us Placostylus,etc.,and unlike 

 Bulimulus. The genital system is identical with that of Bulimulus 

 and Drymseus in B. melo, and also in the other species examined, ex- 

 cept for the somewhat conflicting statements regarding the apex of 

 the penis and its retractor muscle, which call for re-examination. 

 The kidney is strictly Bulimuline, according to Semper; but the 

 ancient and probably not very exact figure in the Regne Animal 



