880 PROCEEDINGS OF THE NATIONAL MUSEUM. VOL.XX. 



was formerly thought to be a variety. It differs, however, in its larger 

 size, more ovate form, the posterior end being more produced and 

 tapered, and in its stronger sculpture. N. corpulentaDallis narrower, 

 more elongated, with more prominent beaks. N. quadrawgularis (D&I1) 

 is shorter and more triangular in form, with the postero-dorsal margin 

 more oblique. 



Subfamily TIND^ItlNJE A^errill and Bush. 



CuciiUeUhi<r FISCHER, Manuel Conch., p. 981, 1887 (in part). 



Tindarinw VERRILL and BUSH, Amer. Jonrn. Sci., III. pp. 58, 63, January, 1887. 



The genus Tindaria differs so widely from Malletia and other genera 

 that it seemed necessary to establish a new subfamily for it. 



In this group the shell is rather thick, short-ovate or veneriforin, with 

 the posterior end the longer, and with the beaks turned forward. The 

 resilium is wanting. The ligament is well developed and prominent. 

 The teeth are numerous, V-shaped, in two series which are frequently 

 continuous proximally. There is neither pallial sinus nor true siphons. 

 The mantle is broadly open ventrally, but there is a separate anal or 

 efferent orifice surrounded by small sense papilla?. The palpi are 

 large, with long, slender appendages. The foot has a large, terminal, 

 crenulated disk. 



This group agrees with Malletina 1 in having no resilium, but the 

 latter has well developed siphons and a pallial sinus. 



TINDARIA Bellardi, 1875. 



Tindaria VERRILL and BUSH, Amer. Journ. Sci., Ill, pp. 58, 63, January, 1897. 



Type. Tindaria arata Bellardi. 



Several recent writers on these shells have regarded Tindaria as a 

 subgeuus of Malletia. In reality they form two widely diverse genera 

 and have little resemblance except that in both the resilium is want- 

 ing. In typical Tindaria the shell is swollen, short-ovate or subcor- 

 date, without any rostration, with prominent umbos and with the 

 beaks turned forward. In fact the shell may be described as veneri- 

 forin. The surface is usually concentrically grooved. The series of 

 teeth are often continuous medially. There is no pallial sinus. 



A specimen of T. amabilis Ball 1 from station 2385, among Forami- 

 nifera, in 730 fathoms, not very well preserved in alcohol, has the 

 mantle closed for a short distance behind the anal orifice which is large 

 and surrounded by twelve or more, rather large, unequal papilla 1 , but 

 does not appear to be capable of being protruded in a tubular form, 

 unless a very short one. The mantle is otherwise freely open along 

 the whole ventral margin to the oral area, with its edges nearly plain, 



^Malletia (Tindaria) cytUerea Dall, Bull. Mus. Cornp. Zool., XII, p. 254, 1886; 

 XVIII, p. 438, 1889; = Malletia amaUlis Dall, p. 438; = Tindaria amaUHs Dall, pi. XL, 

 fig. 8. 



