245 °° PROCEEDINGS OF THE MALACOLOGICAL SOCIETY. 
The exact dimensions of a medium-sized spirit specimen are : — 
. Length over back from head to tip of tail, 33 mm. 
. Length of sole, 81 mm. 
. Width of back, 10mm. 
_ Breadth of sole, 3°5 mm. 
Breadth of groove between sole and back, 2°5 mm. 
. Distance of anus from right tentacle, 6mm. 
. Distance of anus from pulmonary orifice, 5 mm. 
. Distance of pulmonary orifice from head, 8 mm. 
SIAR WN 












Median dorsal groove continued to the head. Anal opening close to 
foot margin. Genital opening close behind the right tentacle. Young 
specimens found near Auckland had only an oval space round the 
- pulmonary orifice, coloured dirty yellow; the others lacked pig- 
mentation, being semi-transparent, whilst some of the internal organs 
could easily be distinguished. In alcohol they became opaque lke 
other specimens. 
A. bitentaculatus is the most common species of the genus, and is 
more abundant in the North Island than in the South, where 
A. papillatus partially takes its place. It is said to occur also on 
the Chatham Islands, but I have not seen any specimens from that 
locality. ) 
2. ATHORACOPHORUS ANTIPODUM (Gray, em.). 
Janella antipodarum, Gray: Ann. Mag. Nat. Hist., vol. xu (1853), 
p. 414; and Proc. Zool. Soc., 1858, p. 112. 
A. bitentaculatus, auct., non Quoy & Gaimard. 
The back is more rounded than in A. bitentaculatus, the colo 
brighter, and spots or dashes of brown or black are entirely absent. 
Its generative system was described and figured by Collinge! under 
the name of Janella bitentaculata, showing that Athoracophorus antt- 
podarum is really distinct. 
Gray does not give any special description of the species, but bases 
on it the diagnosis of his genus Janella. Cockerell, on examining the 
type-specimen in the British Museum, made it a form of A. bitentacu- 
latus, saying ‘‘the variety differs from the type in being witho t 
spots.” * This evidence shows that Collinge’s Janella bitentaculata is 
really Athoracophorus antipodarum, and that his Janella maculata must 
be Athoracophorus bitentaculatus, There is only one other species 0 
the section Athoracophorus, A. dubius, which has the same colour: 
markings as A. bitentaculatus. It differs from the latter, however, 
in several points, as will be shown further on. | 
A. antipodarum is distinguished from A. bitentaculatus by thé 
absence of darker spots, the more highly rounded back, the lon; 
' Proc. Zool. Soc., 1894, pp. 528, 529. 
* Proc. Zool. Soc., 1891, p. 217. 
