JUKES-BltOWXE : DOSIXIA AND ITS SUBDIVISIONS. 99 



except in having the curious groove. He has never seen or heard of 

 a second specimen. Thus Dr. Ball's Dosinisca is based on a freak or 

 deformed specimen, and has no real existence, because there is no 

 group possessing all the characters indicated in his definition. Whether 

 u second similar deformity exists in the U.S. National Museum, or 

 whether Dr. Dall carelessly adopted Reeve's species without making 

 any in(i[uiry, is only known to himself, but the name Bosinisca -will 

 liave to be abandoned. 



Dosinella. — Here, again, Dr. Dall separated a single species to 

 constitute a section by itself ; at least he evidently thought he was 

 doing so, though I am of 0[)inion that the species in question, 

 B. anxjnhui, is only the extreme form of a small natural group, for 

 which the name Bosinella may consequently be adopted. 



The special characters of B. angulosa are stated by Dr. Dall in the 

 following terms: "Valves sub-orbicular with a shallow, flatfish lunule; 

 the escutcheon narrow, flatfish, hardly defined ; pallid sinus ample, 

 ascending, deep, bluntly rounded at the anterior end ; anterior lateral 

 and right posterior cardinal teeth absent or obsolete." He further 

 explains that the peculiar sinus and the obsolescent teeth of this form 

 led him, "after some hesitation, to separate it sectionally." 



It would seem, therefore, that he was unacquainted with B. Brnguieri 

 (Gray) and B. 'penicillata (Reeve), whicli have precisely the same form 

 of sinus, and very small anterior lateral teeth ; they have, in fact, all 

 the same shell-characters except that of the obsolescent posterior left 

 cardinal, for I presume that Dr. Dall really meant the left cardinal 

 and not the ricjlit as printed. 



In B. penicillata, which is an Australian and Philippine species, the 

 anterior lateral tooth is obsolescent in the adult, tliough quite well 

 developed in a young specimen sent me by Mr. E. J. Bantield from 

 Dunk Island, Queensland. In B. Bruguieri this tooth is still obvious 

 in full-grown shells, though small and low. 



B. angulona and B. penicillata are also characterized by the complete 

 absence of the second posterior cardinal in the right valve of the adult 

 shell, though it exists as a faint line in the young, and again this 

 feature persists in the adult B. Bruguieri. 



Thus the three species form a series with angulosa at one end and 

 Bruguieri at the other. The B. funiculata of Romer is probably only 

 a variety of anqtdosa, but the B. cnrrxigata of Reeve may be a good 

 species, and if Ilcimer's fuller description of it is correct it also would 

 appear to belong to this group. B. dilecta of Adams, from Siam (as 

 figured by H. Lynge '), also appear to belong to Bosinella. 



I have now reviewed all the sections proposed by Dr. Dall, and it 

 will be seen that they are not all satisfactory natural groups. Four 

 of them can stand, namely, Orhieulus (= Pcctunculus), Atistrodositiia, 

 Bosinidia, and Bosinella, while Bosinorhis and Bosinisca should be 

 dropped as useless. Eut there are a number of well-known species of 

 Bosinia which cannot be referred to any of these sections, at any rate 

 as I have interpreted them, nor do they belong to the typical (Afruana) 



' Man. Acad. Roy. Sc. et L. de Danemark, ser. vii, t. v, p. 100, 1909. 



