98 PROCEEDINGS OF THE MALACOLOGICAL SOCIETY. 



loft middle cardinal is grooved near the top, but tliat of the riglit is 

 not bifid. 



Dr. Dull states that "this group is represented in 'New Zealand and 

 Japan", but what special Japanese species he would group with amis 

 I cannot imagine, for Japonica is quite different, both as regards 

 escutcheon and teeth. The fact is that D. anus has peculiarities 

 which are shared by few other species, those which come nearest to it 

 being in my opinion D. histrio, D. variegata^ and D. laminata; but 

 I should group in this section D. juvenis, D. scalaris, B. Gruneri, 

 D. cm-uUa, I). EJrmissi, and D. ferruginea, which are similar in 

 dentition ai\d form of pallial sinus. 



Bosinorhis. — It will be convenient to take this supposed section 

 next, Dr. Dall having created it for a single species, D. bilioiulafa, 

 which, he says, " appears to be unique in the genus." The only unique 

 feature about this species is the so-called double lunule, for all its 

 other characters are shared by D. Jajwnica and other species. More- 

 over, there is only one real lunule, the outer one being merely 

 an area of the anterior border defined by a sudden interruption of the 

 concentric riblets which ornament the shell ; these terminate anteriorly 

 in erect crests along a definite line, thus limiting an area which 

 resembles that of the escutcheon ; but it is not a lunule, only a peculiar 

 featui'e of the surface sculpture. No good purpose can be served by 

 separating a single species under the guise of a 'section' when its 

 special characteristic is not correlated with other peculiarities, and is 

 therefore merely a specific character. 



Dosinisca. — In the definition of this section and in the choice of 

 D. data (lleeve) as its typical species, Dr. Dall has excelled himself. 

 His definition is as follows : " Areas of the lunule and escutcheon 

 pouting mesially, defined by a deep sulcus, forming a posterior wing 

 which recalls PhacoifJes {= Lucina); sculpture of fine, rather distant 

 sharp lamella3, sometimes with radial striation ; pallial sinus deep and 

 angular." He adds this group is distributed in Australia and Japan. 



i\ow there are several species of which the lunular and escutcheon 

 areas may be said to pout mesially, but only two species have ever 

 been represented as possessing a groove or sulcus on the posterior side ; 

 these are D. liicinalis (Lam.) and D. alata (Reeve). Of the first 

 very little is known. Mr. E. A. Smith informs me that it was figured 

 by Delessert,^ and that the type is doubtless at Geneva ; also that the 

 delineator of Chenu's Illustrations Conchyliologiques seems to have had 

 a specimen of the true lucitialis before him, though not the actual 

 type. No one else seems to have seen a specimen, for though it is 

 mentioned by Hanley and Homer they clearly did not know the shell. 



Of B. alata I could learn nothing beyond the description given by 

 lleeve, and so far as I could ascertain no private collector in England 

 possessed a specimen. I then applied to Mr. E. A. Smith, who kindly 

 informed me that the type of JD. alata is in the British Museum, and 

 that he regarded it as merely an abnormal specimen of D. pkoia, 

 lleeve ; the type of alata being identical with plana in every respect 



' Recueil coqniUes de Lamarck, pt. ix, figs. 2, «-c. 



