EEPOET ON THE GASTEROPODA. 137 



below the suture and iu the umbilicus, are much rarer and more prominent than else- 

 where. Spirals — there are sharpish rounded spiral threads on all the whorls, those 

 on the earlier whorls are three or four, and are subequal ; on the last there are 

 above the periphery about four larger, with smaller ones between, while on the base 

 they are numerous, both without and within the umbilicus ; one in particular in the 

 middle of the base is strong, and another, within the funnel, is nearly as much so ; these 

 spirals are faintly crossed by the longitudinal lamella? ; but within the umbilicus the 

 lamellae form minute spines or tubercles on the crests of the spirals. Colour a cindery 

 yellow with a ruddy tinge, and flecked above, especially on the highest spiral, with 

 brilliant little crimson spots ; 1 the upper part of the spire is bright yellow, the apex pale. 

 Spire depressed, conical, scalar. Apex rounded, polished, the tip scarcely prominent ; 

 the embryonic tip seems, as usual, introverted. Whorls 5, of very gradual and regular 

 increase, with a flat, horizontal or slightly sunken shoulder below the suture. Suture 

 distinct, being angulated and a very little impressed. Mouth round, very oblique, small. 

 Outer lip thin, very slightly patulous, with a very feeble white callus within. Inner lip 

 has a very short attachment to the body, is rounded, and a little patulous. H. 0'16 in. 

 B. 0-24. Penultimate whorl, breadth 0*05. Mouth, height 0-09, breadth 0"09. 



This very pretty little species is not like any other I know, and rather recalls in form some 

 of the Solariella group of Trochus ; but the mouth, inner lip, texture of shell, and apex are unmis- 

 takably those of Solarium. There are in this specimen, on the last whorl especially, some minute 

 stumpy setae, which are probably embryonic seaweed. They are too irregularly arranged to make it- 

 likely they should be traces of any epidermis. 



2. Bifrontia," Deshayes, 1833. 

 Bifrontia (?) pernambucensis, n. sp. (PI. VIII. fig. 13). 



Station 122. September 10, 1873. Lat. 9° 5' N., long. 34° 50' W. Off Pernambuco. 

 350 fathoms. Eed mud. 



SJiell. — Small, discoidal, white, polished, ribbed, and spiralled, with a depressed spire, 

 a mamillated apex, an impressed suture, a disjoined and slightly quadrangular mouth, 

 and a wide open, scarcely impressed umbilicus. Sculpture: The last two whorls are 

 obliquely girt round with about twenty thin, small, slightly procumbent, distant lamellae, 

 between which are slight striae. Spirals— there are small, feeble, rounded threads and 



1 These suggested the name. 



2 Deshayes in 1832 at first proposed (Encyclop. method., vol. iii. p. 659) for this genus the name of Oma- 

 laxis (not Omalalaxis, see Hermamisen Index Gen. Malak. Prim., vol. ii. p. 144), which is neither Greek nor 

 Latin, nor even a mixture of the two. In 1833 he himself (Coq. Foss. Par., vol. ii. p. 222) substituted for this 

 hybrid Bifrontia, which has been largely accepted, the more so that the change to Homolaxon, proposed by 

 Agassiz (Nomenclator sub voce), is complicated by a slip of the pen, and Homalaxis, which has been suggested, 

 is no escape from the essential wrongness of the original word, which were best allowed to lapse. 



(ZOOL. CHALL. EXP. PAET XLII. 1885.) Tt 18 



