MancJiester Memoirs, Vol. xlviii. (1904), No. *i\. 19 



the median rib of the rhachis is bluntly elevated in front, and 

 less cornified than the lateral margins ; behind it is narrow, 

 sharply elevated into a keel and more strongly cornified, but 

 scarcely perceptible through the integument. 



Onychoteuthis banksi : — Hinder end of the fin of the adult 

 moderately produced, so that the fin is wider than long ; the 

 carpal fixing apparatus consists of 7 to 10 suckers and pads ; the 

 fifth or sixth proximal hook of the dorsal row is suddenly 

 displaced towards the ventral row of large hooks ; the suckers of 

 the arms for the most part have a pear-shaped prominence ; the 

 pen in its middle part has a distinct narrow web, which is not 

 connected with the spoon-shaped cone at the hinder end ; the 

 solid spine is only of moderate length ; the median rib of the 

 rhachis is strongly elevated, rising into a very high and strong 

 keel behind ; anteriorly it is much more strongly cornified than 

 the lateral margins, and is clearly perceptible as a sharp dark- 

 coloured line through the integument. 



1 2. The information at present available regarding these two 

 genera is very meagre : I am indebted to my friend Dr. Pfeffer 

 for the following notes regarding them, " Tetronychoteiithis : 

 according to d'Orbigny's figure the Paris specimen would appear 

 to have been in the stomach of a Cetacean, so that it no longer 

 possesses either horny rings or hooks, neither has the Hamburg 

 specimen any. I have inferred from the form of the fleshy 

 remains that it originally had four rows of hooks. I am now, 

 however, very uncertain on the point for Lycoteuthis possesses 

 four rows of suckers with round rings. The Hamburg and 

 Strasburg specimens have no longer any horny structures, but 

 the examples from the 'Valdivia' Expedition have four rows 

 with round rings ; they are, however, rather small. Lycoteuthis 

 is an undoubted Onychoteuthid." 



13. See Chun, Ueber Leuchtorgane und Augen von 

 Tiefsee-Cephalopoden, Verh. Deutsch. Zx)ol. Gesellsch., vol. 13, 

 p. 67-82, 1903 ; the genus has not yet been formally diagnosed ; 

 no information is yet forthcoming as to its fins, suckers, or other 

 important characters ; hence this portion of the key can only be 

 regarded as provisional. 



