96 University of Michigan 



Typical honadrensis (Table IX, B2) from southern and cen- 

 tral Bonaire (Bl, 2, 7) and Klein-Bonaire (Kl) is quite dis- 

 tinct in form and sculpture from any of the other subspecies. 

 However, those from the more northern localities (B5, 6, 8) 

 are more slender and elongate (Table IX, B8), and the growth 

 riblets of the lower whorls are weaker and less regular, so 

 these shells intergrade somewhat with the series from Curagao, 

 especially with the lots from the more northern localities of 

 that island. 



In Table IX, the minor diameter is used because of its 

 greater constancy and on account of the difficulty in the meas- 

 urement of the major diameters of these small shells by means 

 of calipers. Throughout this paper, all measurements that 

 involve two decimal places were made from camera-lucida 

 drawings under considerable magnification. It will be noted 

 that I did not obtain any specimens as small as Smith's meas- 

 urements would indicate, but this may be due to the fact that 

 his figures are only to the nearest half -millimeter. 



Table IX. Dimensions of Microceramus bonairensis 



Microceramus bonairensis curacoanus H. Burrington Baker 

 Macroceramus inermis Gibbons (1879; J. of C, II, 136) ; first Curasao 

 record; W. G. Binney (1883; Ann. K Y. Acad. Sci., Ill, 126); radula. 

 Microceramus honai/rensis curacoana H. B. Baker (1923; Occ. Papers Mus. 

 Zool. Univ. Mich.; no. 137, p. 6-7; figs. 1-4, 5). 



Type locality: (C5c) Schaarlo, back of Willemstad, Curagao. 



Distribution: Curagao; under limestone rocks (Cl-7, 11-13, 

 17, 20). 



Shell (fig. xvii-75) : more elongate but slightly smaller than 

 typical bonairensis. Color: light corneous to dark brown; 

 opaque calluses more conspicuous than in preceding. Whorls : 

 about 10; less convex and with shallower suture than in 



