Pterotrachea.] GASTROPODA. 



Animal large, whitish, transparent : body smooth, except the 

 medio- ventral and lateral parts, which possess small white opaque 

 tubercles ; there are 6 to 8 distinct frontal tubercles, arranged in two 

 series ; ventral fin very large, oval, rounded, inserted at a little behind 

 the middle of the body. Visceral sac relatively large, with 16 gill- 

 filaments of medium size ; posterior end relatively short, tricarinate 

 above, bicarinate below, with a bilobate caudal fin. Upper part of 

 the buccal orifice with 2 rows of unequal hooks. Radula having the 

 formula 2+1+1+1 + 2. 



Length of New Zealand specimen, about 320 mm. 



Anatomy. Leydig. Zeitschr. f. wissenschaftl. Zoologie, iii, 328. 



Hal. Long Beach, north of Otago Harbour (W. Fels). Also 

 Mediterranean. 



SUBORDER 2. STENOGLOSSA. 



Pectinibranchs in which the nervous system is much concentrated. 

 The perioesophageal nerve-collar is always posterior to and is not- 

 traversed by the salivary glands. A well-developed proboscis, an un- 

 paired oesophageal gland (the gland of Leiblein, or poison-gland), a 

 pallial siphon, and a verge are always present. The radula is narro\v. 

 and in the majority of genera (Rachiijlossa) has a single lateral on each 

 side of the median tooth ; in the remainder of the group (Toxoijlossa) 

 there is no median tooth, and the radular formula is therefore 1 + 0+1. 



Tribe 1. RACHIGLOSSA. 



These are Stenoc/lossa with a highly developed proboscis, a pallia! 

 siphon, and rudimentary jaws ; the radvlar formula is 1 + 1+1. 



Fam. TURBINELLID^E, Sowerby. 



Animal with a small head, tentacles convergent at the base, with 

 the eyes on the outer sides ; proboscis long ; foot broad. Radula 

 triserial, the central tooth always tricuspidate. the lateral teeth mostly 

 bicuspidate, the cusps of unequal length. 



Shell solid, p) ^iform or fusiform, \\ith a rather long canal ; columella 

 more or less tHckened, \\lth plaits or sometimes smooth. Operculum 

 corneous, oval-unguiform, the nucleus apical. 



Genus 1. MEGALATRACTUS, P. Fischer, 1884. 



Megalatractus, P. Fischer, Man. tie Conch., 1884, 623. Type : Fusus pro- 

 boscidiferv?, Lamarck = aruanus, Gmelin. Syrinx, Bolten, Mus. Bolten.. 

 1798, 121 ; not of Bohadsch, 17(51. 



Shell large, fusiform, widened in the noddle, prominently spirally 

 Hrate, narrowly umbilicated. 



Anatomy. Kesteven, Mem. A.M., iv, 1904. 

 Distribution. Australia, Tasmania, and New Zealand. 

 The genus is found in depths ranging from 20 to 10) fathoms. 

 12* 



