REPORT ON THE GASTEROPODA. 465 



Family Tubulibranchia, Cuvier, 1830. 

 Genera. 1, Ccecum, Fleming. 2. Vermetus, Adanson. 3. Siliquaria, Bruguiere 



1. Ccecum, Fleming, 1824. (See Appendix No. 6.) 



2. Vermetus, Adanson, 1757. 



Vermetus (?) cyclicus, 1 n. sp. (Pk XXXI. fig. 1). 



September 8, 1874. Flinders Passage, Cape York, North-east Australia. 7 

 fathoms. 



Station 186. September 8, 1874. Lat. 10° 30' S., long. 142° 18' E. Wednesday 

 Island, Cape York, North-east Australia. 8 fathoms. Coral mud. 



Shell. — Small, thin, white, discoidal, of slow and regular increase, with the coiled-up 

 embryonic tip of a Ccecum : below this the early part of the shell is straight and polished, 

 with only very feeble microscopic annular lines, and rises out of the plane of the disc, but 

 is attached to the succeeding whorl across which it lies ; all the latter part of the shell is 

 sparsely and circularly ribbed as in Scalaria ; the whole surface, including both the ribs 

 and the much wider interstices, is fretted with exquisitely delicate, sharp, and regular 

 longitudinal scratches, of which about five go to the thousandth of an inch ; there are 

 also between the ribs very feeble, narrow, and sparse circular threadlets, which only 

 appear as being faintly translucent on the dead frosted surface ; there is about one of 

 these to each thousandth of an inch ; exclusive of the embryonic apex of 1^ whorls, 

 and exclusive also of the little straight part which follows, the shell presents about 

 lij whorls, which are discoidally coiled, adjacent, and adherent to one another ; the mouth 

 is circular. 



Height (exclusive of projection of embryonic shell), 0*019 in., height (including this 

 projection), 0*027. Breadth, 0*035; breadth of last whorl at mouth, 0*017; breadth of 

 embryonic tip, 0*0044. Length of tip and smooth part, 0*019. 



This is a very curious and beautiful little shell, whose generic place is very doubtful. Ctiloceras 

 or Ramshorn suggested itself as a suitable name for a new genus near Ccecum, but the creation of 

 a new genus could really not be justified for a shell about which so little is known. 



1 xuxXixo;, circular. 



(ZOOL. CHALL. EXP. — PART XLII. — 1885.) Tt 59 



