58. 



Manchester Memoirs, Vol. xlviii. (1904), No. 31. 13 



^Articulating facet at the base of the siphon an elongated 

 pit, without a transverse groove ; articulating facet 

 on the inner surface of the mantle a linear ridge 

 without any transverse ridge 59 



Articulating facet on the siphon sub-triangular; facet 

 on the mantle with longitudinal and transverse ridge, 

 JL-shaped , or H-shaped 65 



Articulating facet on siphon ear-shaped with an 

 elevated margin ; on the mantle a rounded 

 tubercle, or a ridge with posterior elevation 



(Chiroteuthid^e) 73 



'Numerous luminous organs on the ventral aspect of 

 the body, siphon, head and arms. 



59-1 (HiSTIOTEUTHIDiE) 6o 



No luminous organs 62" 



60. 



'Horny rings of arm-suckers without teeth Calliteuthis, 



^Horny rings of arm-suckers toothed 61 



''In the adult an extensive web connecting all the arms 

 except the ventral (in the young the web may be 

 absent or rudimentary) ; luminous organs in a single 

 row on the dorsal and lateral arms ; three and two 

 rows on the ventral Histioteuthis. 



61.- 



Web rudimentary ; luminous organs close-set and 



numerous ; on dorsal and dorso-lateral arms three 



rows, on the ventro-lateral four and on the ventral 



I eight; and a single row of cartilaginous tubercles on 



I the outer side of the dorsal and lateral arms and along 



^ the dorsal middle line of the mantle . . . Mekagroteuthis}'' 



